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PHYSICS OF SEMICONDUCTORS: 30th International Conference on the Physics of Semiconductors Date: 25–30 July 2010 Location: Seoul, (Korea) ISBN: 978-0-7354-1002-2 Editor(s): Jisoon Ihm, Hyeonsik Cheong

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Plenary and Invited Papers published in the 15 May 2011 Special Topic section of Journal of Applied Physics

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Preface: Physics of Semiconductors

Jisoon Ihm and Hyeonsik Cheong

AIP Conf. Proc. 1399, pp. 3-3; doi:http://dx.doi.org/10.1063/1.3671439 (1 page)

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89.20.Hh World Wide Web, Internet
75.50.Pp Magnetic semiconductors
85.30.De Semiconductor-device characterization, design, and modeling

Magnetic Field Modulated Photoreflectance Study of the Electron Effective Mass in Dilute Nitride Semiconductors

N. Mori, K. Hiejima, H. Kubo, A. Patanè, and L. Eaves

AIP Conf. Proc. 1399, pp. 23-24; doi:http://dx.doi.org/10.1063/1.3666239 (2 pages)

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Magnetic field modulated photoreflectance measurements are performed on the dilute nitride semiconductor Ga(AsN) in quantizing magnetic fields. From the measured cyclotron energies, the conduction band effective mass and its dependence on the nitrogen content are determined. The effective mass is found to become significantly heavier in samples with high nitrogen composition (>0.1%).
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07.55.Db Generation of magnetic fields; magnets
03.70.+k Theory of quantized fields
78.20.Mg Photorefractive effects
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)

New origins of stimulated emission and temperature dependence in ZnO

Bumjin Kim, Doman Kim, Chaeryong Cho, Norihiro Tamura, Tatsushiro Yamazaki, Akihiro Murayama, and Kwangseuk Kyhm

AIP Conf. Proc. 1399, pp. 25-26; doi:http://dx.doi.org/10.1063/1.3666240 (2 pages)

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Lasing mechanisms in ZnO near the Mott density was investigated by temperature dependent gain in a ZnO thin film using a variable stripe length method (VSLM). Below the Mott density, gain is attributed to exciton‐longitudinal optical phonon scattering and inelastic exciton‐exciton scattering, which are dominated up to 130 K. Above the Mott density, we found an additional gain mechanism of electron‐hole plasmon‐phonon mixed state, which survives up to RT.
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72.10.Di Scattering by phonons, magnons, and other nonlocalized excitations
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons
71.15.Nc Total energy and cohesive energy calculations
61.72.Mm Grain and twin boundaries

Electronic Structure Of ZnTe:O

Byounghak Lee and Lin‐Wang Wang

AIP Conf. Proc. 1399, pp. 27-28; doi:http://dx.doi.org/10.1063/1.3666241 (2 pages)

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Highly lattice mismatched semiconductors are promising candidates for multiple‐band solar cell materials. Using the newly developed linear scaling three dimensional fragment method, we found that ZnTe1−xOx can be used for an intermediate‐band state solar cell material with a theoretical efficiency of 63%. We show that the intermediate band states in this system is a result of the coupling between oxygen impurity states, contrary to the previous claim that the intermediate‐band states are due to the coupling of the impurity state with the conduction band states.
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84.60.Jt Photoelectric conversion
71.20.Gj Other metals and alloys
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
71.35.Ee Electron-hole drops and electron-hole plasma

Electrically Enhanced Infrared Photoluminescence in Cr:ZnSe

Julien Jaeck, Riad Haidar, Fabrice Pardo, Jean‐Luc Pelouard, and Emmanuel Rosencher

AIP Conf. Proc. 1399, pp. 29-30; doi:http://dx.doi.org/10.1063/1.3666242 (2 pages)

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A six‐fold enhancement of infrared photoluminescence from thick single crystal Cr:ZnSe under electrical excitation is reported. The baseline 2–3 μm photoluminescence signal is obtained under a charge‐transfer band optical seeding. The electrically enhanced infrared signal is localized under a semi‐transparent cathode and is shown to be likely related to hole concentration. The various mechanisms of excitation involved in this infrared light emission will be discussed.
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78.20.Jq Electro-optical effects
42.55.Px Semiconductor lasers; laser diodes
42.25.Bs Wave propagation, transmission and absorption
42.50.Ar Photon statistics and coherence theory

Transport and Thermoelectric Properties of Sn‐filled∕Ni‐doped CoSb3 Skutterudites

Jae‐Yong Jung, Kwan‐Ho Park, and Il‐Ho Kim

AIP Conf. Proc. 1399, pp. 31-32; doi:http://dx.doi.org/10.1063/1.3666243 (2 pages)

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SnzCo3.7Ni0.3Sb12 skutterudites have been successfully synthesized by induction melting followed by annealing at 823 K for 120 h in a vacuum, and the Sn filling effects on the transport and thermoelectric properties were examined. Seebeck coefficient and Hall coefficient confirmed that electrical conduction type was changed from n‐type to p‐type if the filling fraction (z) is higher than 0.4. The temperature dependence of electrical resistivity suggests that SnzCo3.7Ni0.3Sb12 is a highly degenerate semiconducting material. The thermal conductivity was reduced by Sn filling and the lowest thermal conductivity was achieved for the compound Sn0.2Co3.7Ni0.3Sb12.
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85.80.Fi Thermoelectric devices
81.16.Be Chemical synthesis methods
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
61.72.Qq Microscopic defects (voids, inclusions, etc.)

Temperature Dependent Charge Transport Properties Of P‐type Cux(CdTe)yOz Films Studied By Au Ohmic And Schottky Contacts

Victor‐Tapio Rangel‐Kuoppa, Sujel‐Melina Murillo‐Polania, J. Carmona‐Rodríguez, R. Lozada‐Morales, J. Márquez‐Marín, and S. Jiménez‐Sandoval

AIP Conf. Proc. 1399, pp. 33-34; doi:http://dx.doi.org/10.1063/1.3666244 (2 pages)

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Temperature dependent current voltage measurements were done on five samples of Cux(CdTe)yOz grown by reactive rf cosputtering. The stoichiometry of the samples were different and in the high copper and oxygen concentrations regime. An Al and a Au contact were used. The Al contact was always ohmic. Depending on the composition, the Au contact yielded either a Schottky or an ohmic behavior. In the case of an ohmic behavior, one sample yielded temperature independent results, while another temperature dependent parameters. In the case of Schottky behavior, the Cheung method was used to obtain the internal resistance and the ideality factor. The current voltage behavior is well explained by tunneling, and three activation energies of 62, 89 and 186 meV are obtained for each sample. Finally, a negative differential resistance effect is found in one sample, the only one where it was possible to detect CuO and Cu2O nanoclusters using the X‐ray diffraction technique.
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61.66.Bi Elemental solids
61.66.Dk Alloys
73.40.Cg Contact resistance, contact potential
73.30.+y Surface double layers, Schottky barriers, and work functions
61.05.cp X-ray diffraction

Electrical Properties Of GaN Layers Grown By Metal Organic Vapor Phase Epitaxy (MOVPE)

Victor‐Tapio Rangel‐Kuoppa, Cesia Guarneros Aguilar, and Victor Sánchez‐Reséndiz

AIP Conf. Proc. 1399, pp. 35-36; doi:http://dx.doi.org/10.1063/1.3666245 (2 pages)

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The electrical properties of three un‐doped GaN samples grown at low pressure by Metal Organic Vapor Phase Epitaxy (MOVPE) on sapphire substrates are reported. Two different growth temperatures of 900 °C and 950 °C were used, for 90 min. Also, two trimethylgallium flow fluxes were set (5.39 μmole∕minute and 8.39 μmole∕minute). The temperature dependent Hall (T‐Hall) technique was used, between 35 K and 373 K. The resistivity of our samples fluctuated between 3 and 24 mΩ×cm. They were temperature dependent and were explained by two thermally activated processes, with activation energies of 20 and 70 meV. For the two samples grown at 900 °C, the mobilities and the charge carrier densities were temperature independent with values of 10 and 20 cm2 V−1 s−1, and 6×1019 and 5×1019 cm−3, respectively. For the sample grown at 950 °C, the mobility showed temperature dependence to the power of +1/3 and the charge carrier density a thermally activated dependence with an activation energy of 5 meV.
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81.15.Kk Vapor phase epitaxy; growth from vapor phase
72.20.My Galvanomagnetic and other magnetotransport effects
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
84.37.+q Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.)

Temperature dependence of the dielectric response of AlSb

Y. W. Jung, T. J. Kim, Y. D. Kim, S. H. Shin, S. Y. Kim, and J. D. Song

AIP Conf. Proc. 1399, pp. 37-38; doi:http://dx.doi.org/10.1063/1.3666246 (2 pages)

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Spectroscopic ellipometry was used to determine the optical response of an intrinsic AlSb film as a function of temperature. The 1.5 μm thick film was grown on a (001) GaAs substrate by molecular beam epitaxy. Measurements were done at temperatures from 300 K to the growth temperature of 800 K over a spectral range of 0.7 to 5.0 eV. To avoid oxidation artifacts, measurements were done with the film in situ. The data were analyzed using a parametric semiconductor model for its temperature dependence.
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85.40.Xx Hybrid microelectronics; thick films
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.65.Mq Oxidation
07.20.Dt Thermometers
07.05.Kf Data analysis: algorithms and implementation; data management

The Excitonic Wave‐packet Motion In GaSe Probed By Spectrally Resolved Four‐wave Mixing Spectroscopy

Hirokazu Tahara, Yoshihiro Ogawa, and Fujio Minami

AIP Conf. Proc. 1399, pp. 39-40; doi:http://dx.doi.org/10.1063/1.3666247 (2 pages)

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We have observed the excitonic wave‐packet motion through spectrally resolved four‐wave mixing measurements in a layered semiconductor GaSe, and demonstrated that the four‐wave mixing spectroscopy is a useful tool to observe the wave‐packet motion. We have found that the wave‐packet motion in a quasi‐two‐dimensional system is explained theoretically by using the configuration coordinate model, where the adiabatic potential curve is shifted due to the exciton‐phonon interaction.
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42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
71.35.Gg Exciton-mediated interactions
42.65.Yj Optical parametric oscillators and amplifiers
42.55.Px Semiconductor lasers; laser diodes

Temperature Dependence of Photoluminescence Peak Energy in Ga(In)NAs

Shuichi Emura, Hiroki Nakamoto, Fumitaro Ishikawa, Masahiko Kondow, and Hajime Asahi

AIP Conf. Proc. 1399, pp. 41-42; doi:http://dx.doi.org/10.1063/1.3666248 (2 pages)

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Introducing normal coordinate system, theoretical approach to band gap alteration with temperature is described. The derived expression is applied to a GaNAs system having the nitrogen composition of about 1.4%. It is found that the band gap narrowing in this system is originated in the inter‐band mixing assisted by an LO phonon at a Γ point through electron—phonon interaction.
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71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)
78.55.Cr III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
71.20.Nr Semiconductor compounds

Physical properties of Mn oxypnictide (LaO)MnPn; Pn  =  P, As, Sb

M. Onizawa, S. Otsuka, R. Takeda, K. Kato, N. Umeyama, S. Ikeda, S. Hiramoto, F. Yoshida, C. Moriyoshi, Y. Kuroiwa, K. Tobimatu, H. Sato, M. Sawada, H. Namatame, M. Taniguchi, et al.

AIP Conf. Proc. 1399, pp. 43-44; doi:http://dx.doi.org/10.1063/1.3666249 (2 pages)

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We have investigated physical properties of the layered Mn oxypnictides (LaO)MnPn; Pn  =  P, As, Sb. Electrical resistivity of three samples, indicting semiconducting behaviors, drastically increases with lowering temperature. The optical band gaps estimated from the diffusive reflectance are about 1.6 eV and they don′t depend on pnictogen atoms even though the lattice constants widely change. Magnetizations of (LaO)MnAs and (LaO)MnSb show very weak temperature dependence with positive slope against temperature. Some magnetic order is expected to exist at higher temperature than room temperature. Consequently, the Mn oxypnictides (LaO)MnPn are magnetic semiconductors.
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75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Pp Magnetic semiconductors
61.66.Bi Elemental solids
61.66.Dk Alloys
71.15.Ap Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)

Physical Properties of the Transition Metal Chalcogenide β‐FeSe

Y. Kaneko, H. Azuma, S. Hiramoto, Y. Matsui, M. Maeda, F. Yoshida, C. Moriyoshi, T. Watanabe, Y. Takano, A. Yamasaki, N. Umeyama, Y. Hara, S. Ikeda, Y. Kuroiwa, and K. Takase

AIP Conf. Proc. 1399, pp. 45-46; doi:http://dx.doi.org/10.1063/1.3666250 (2 pages)

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We have investigated the physical properties of a bulk sample β‐FeSe. This material has a metallic character in electrical properties with ferromagnetism from room temperature to 5 K. Magnetization shows an anomaly around 190 K and Hysteresis loop is still observed below this temperature. This magnetic behavior seems to arise from different temperature dependences of sublattice magnetization of Fe2+ and Fe3+. Namely, β‐FeSe is a typical ferrimagnet with good electrical conductivity.
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75.50.Bb Fe and its alloys
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
85.25.Dq Superconducting quantum interference devices (SQUIDs)
75.20.Hr Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions
79.60.Bm Clean metal, semiconductor, and insulator surfaces

Effect Of Sintering Temperature On The FT‐Spectra Of Erbium Doped Silicate Glasses

Vandana Ranga, R. K. Khanna, H. N. Acharya, and Anirudh Kumar Ranga

AIP Conf. Proc. 1399, pp. 47-48; doi:http://dx.doi.org/10.1063/1.3667010 (2 pages)

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Low processing temperature, homogeneity and high purity are the advantages one attains through hydrolysis and condensation of metal alkoxides to derive oxide glasses when compared with conventional melting techniques. An attempt was also made to explore the effects of varying the aging time of the gels to three years for chemical stability of the glasses produced. The variation of Erbium doped IR Spectra as a function of sintering temperature reveal many interesting results. The maximum absorption peaks around 3400 and 1630 cm−1 are observed for unsintered gels and gradually decrease on increasing sintering temperature thereby suggesting escape of molecular water. The structural indication of Si‐OH bonds is by band at around 960 cm−1. Defect structure is assigned to bands around 750 and 550–600 cm−1 in agreement with the literature available.
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68.03.Fg Evaporation and condensation of liquids
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
61.50.Lt Crystal binding; cohesive energy
64.75.Nx Phase separation and segregation in solid solutions

Strong mid‐infrared optical absorption by supersaturated sulfur doping in silicon

I. Umezu, A. Kohno, J. M. Warrender, Y. Takatori, Y. Hirao, S. Nakagawa, A. Sugimura, S. Charnvanichborikarn, J. S. Williams, and M. J. Aziz

AIP Conf. Proc. 1399, pp. 51-52; doi:http://dx.doi.org/10.1063/1.3666252 (2 pages)

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Single crystalline silicon supersaturated with sulfur was prepared by ion implantation followed by pulsed laser melting and rapid solidification. A strong and broad optical absorption band and free‐carrier absorption appeared for this sample around 0.5 eV and below 0.2 eV, respectively. A possible candidate for the origin of the 0.5 eV band is the formation of an impurity band by supersaturated doping.
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61.72.uf Ge and Si
81.30.Fb Solidification
61.72.sd Impurity concentration
42.55.Lt Gas lasers including excimer and metal-vapor lasers

Determination of Defect Densities in High Electron Mobility Transistors Using Current Transient DLTS

John Palma and Samson Mil'shtein

AIP Conf. Proc. 1399, pp. 53-54; doi:http://dx.doi.org/10.1063/1.3666253 (2 pages)

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Since its introduction, Deep Level Transient Spectroscopy (DLTS) has become the preferred tool for investigating semiconductor defects. The limitations of measuring the small changes in gate capacitance in transistors led to the advent of current transient DLTS where the defects manifest themselves as a small change in drain current. However, this method was introduced at a time when heterostructure devices, such as High Electron Mobility Transistors (HEMTs), were non‐existent and fails in determining defect concentrations in these modern devices. This study establishes a method by which defect concentrations can be determined in HEMT structures using current transient DLTS. First, the relationship between the change in the trap charge and the transistor drain current is established. Then, a computer aided technique is described which determines the volume within the device where the Fermi level crosses the trap energy. The result is that trap densities and their locations can be determined. DLTS measurements revealed two traps with ET  =  0.43 and Nt  =  1.1×1017 cm−3, and ET  =  0.19 and Nt  =  3.1×1017 cm−3 for a tested HEMT.
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84.37.+q Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.)
85.30.Tv Field effect devices
77.22.Ch Permittivity (dielectric function)
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)

Reexamination of the Atomic Configurations of NN Centers and Observation of New Infrared Luminescence Centers in GaP:N

Michio Ikezawa, Masato Watanabe, Yoshiki Sakuma, and Yasuaki Masumoto

AIP Conf. Proc. 1399, pp. 55-56; doi:http://dx.doi.org/10.1063/1.3666254 (2 pages)

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The authors studied luminescence polarization of individual NN centers in GaP:N and discussed the atomic configurations. In addition to the widely known green luminescence centers, NN1 ∼ NN10, new luminescence centers were observed in the infrared spectral region, which may be due to the true nearest‐neighbor NN pair.
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76.70.Fz Double nuclear magnetic resonance (DNMR), dynamical nuclear polarization
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
85.60.Gz Photodetectors (including infrared and CCD detectors)
71.15.Nc Total energy and cohesive energy calculations

The Electronic Structure of Oxygen Vacancy in Amorphous HfSiO4

Hyeon‐Kyun Noh, Byungki Ryu, Junhyeok Bang, Kee Joo Chang, and Eun‐Ae Choi

AIP Conf. Proc. 1399, pp. 57-58; doi:http://dx.doi.org/10.1063/1.3666255 (2 pages)

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We perform first‐principles density functional calculations to investigate the electronic structure of O‐vacancy in amorphous HfSiO4. We find that O‐vacancies surrounded only by Si atoms are energetically most favorable and exhibit the defect levels similar to those of α‐quartz SiO2. When O‐vacancies have a mixture of Si and Hf atoms or only Hf atoms in the neighborhood, they behave as charge traps, similar to those in HfO2. We suggest that Si‐surrounded O‐vacancy defects play a role in improving the threshold voltage instability in HfSiO4‐based metal‐oxide‐semiconductor devices.
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71.15.Mb Density functional theory, local density approximation, gradient and other corrections
71.23.Cq Amorphous semiconductors, metallic glasses, glasses
85.30.Tv Field effect devices
71.15.Dx Computational methodology (Brillouin zone sampling, iterative diagonalization, pseudopotential construction)

Spin, Structure, and Charge of Decavacancy V10 in Crystalline Silicon

Kazuyuki Uchida and Atsushi Oshiyama

AIP Conf. Proc. 1399, pp. 59-60; doi:http://dx.doi.org/10.1063/1.3666256 (2 pages)

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Atomic and electronic structures of decavacancy V10 in crystalline silicon are clarified by first‐principles total‐energy calculations based on the density‐functional theory. Structural relaxation of V10 is found to be a combination of a breathing relaxation and a Jahn‐Teller type distortion of a part of the atoms surrounding the vacant sites. The amount of the relaxations depend on the charge state sensitively, and high‐spin states are obtained in several charge states.
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71.15.Mb Density functional theory, local density approximation, gradient and other corrections
61.72.jd Vacancies
71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect
75.20.Hr Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions

Transition To Impurity Continuum And Thermal Properties Of IV‐VI—based Semiconductor Solid Solutions

E. I. Rogacheva, O. N. Nashchekina, and O. S. Vodorez

AIP Conf. Proc. 1399, pp. 61-62; doi:http://dx.doi.org/10.1063/1.3666257 (2 pages)

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The analysis of earlier obtained experimental dependences of the thermal properties (phonon thermal conductivity, thermal expansion coefficient, and heat capacity) on impurity concentration for PbTe and SnTe‐based semiconductor solid solutions is performed. It is shown that the transition from diluted to concentrated solid solutions is accompanied by anomalies in all thermal properties. The experimental results are analyzed on the basis of percolation theory and fluctuation theory of the second type phase transitions taking into account alloy scattering and spatial correlations of impurity centers.
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71.55.Gs II-VI semiconductors
65.40.De Thermal expansion; thermomechanical effects
64.60.ah Percolation
05.65.+b Self-organized systems

Crystal structure and defect reactions in the kesterite solar cell absorber Cu2ZnSnS4 (CZTS): Theoretical insights

Aron Walsh, Shiyou Chen, X. G. Gong, and Su‐Huai Wei

AIP Conf. Proc. 1399, pp. 63-64; doi:http://dx.doi.org/10.1063/1.3666258 (2 pages)

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Cu2ZnSnS4 (CZTS) is one of the most promising quaternary absorber materials for thin‐film solar cells. Light to electricity conversion efficiencies in CZTS devices have recently reached 9.6%, making it a competitive and more sustainable replacement for existing CdTe and Cu(In,Ga)Se2 (CIGS) thin‐film technologies. We review our recent insights into the structural, electronic and defect properties of this topical material. We have found that the stable crystal structure of CZTS is kesterite, which is derived from the ternary chalcopyrite structure. Examination of the thermodynamic stability of CZTS reveals that the stable chemical potential region for the formation of the stoichiometric compound is small. Under these conditions, the dominant defect will be p‐type CuZn antisite, which has an acceptor level deeper than the isolated Cu vacancy. The dominant self‐compensated defect pair is [CuZn+ZnCu], which leads to the formation of various polytype structures. We propose that to maximize the solar cell performance, growth of CZTS under Cu‐poor∕Zn‐rich conditions will be optimal, if the precipitation of ZnS can be avoided. This theoretical guidance can provide new directions for improving the conversion efficiencies of kesterite based solar cells.
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81.10.Dn Growth from solutions
81.10.Fq Growth from melts; zone melting and refining
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
61.72.Bb Theories and models of crystal defects
61.66.Bi Elemental solids
61.66.Dk Alloys
84.60.Jt Photoelectric conversion

Effect Of Growth Temperature And Annealing Treatment On The Activation Of Nitrogen In ZnO:N Grown By MOCVD

J. K. Dangbégnon, K. Talla, and J. R. Botha

AIP Conf. Proc. 1399, pp. 65-66; doi:http://dx.doi.org/10.1063/1.3666259 (2 pages)

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Metalorganic Chemical Vapor Deposition, which involves a variety of sources containing carbon and hydrogen, may introduce a high concentration of nitrogen‐related defects such as NO‐H, (CN)O and HCN in ZnO. This report shows a correlation between the crystalline quality of ZnO films grown with NO and the diffusivity of carbon and hydrogen species. The activation of nitrogen is studied by the low temperature photoluminescence. Secondary ion mass spectroscopy of annealed samples, grown at 270 °C, 310 °C and 370 °C respectively, shows that the diffusion of the impurities is more efficient in the sample grown at low temperature (270 °C), while only a redistribution of the impurities in the films is observed for the sample grown at the highest temperature (370 °C). Furthermore, the investigation of the optical properties of these samples shows effective more efficient activation of the nitrogen acceptor in the sample grown at low temperature. The activation of nitrogen is concluded by its involvement in two donor‐acceptor pair transitions at ∼3.24 eV and ∼3.17 eV. An additional transition at ∼3.1 eV is also investigated.
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81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
61.72.Bb Theories and models of crystal defects
61.72.sd Impurity concentration
71.15.Nc Total energy and cohesive energy calculations
68.55.jd Thickness

Thermally Stimulated Current Studies On Electron‐irradiated Single Crystal ZnO Bulk: Dual Light Illumination Effect

T. Oga, Y. Izawa, K. Kuriyama, K. Kushida, and Q. Xu

AIP Conf. Proc. 1399, pp. 67-68; doi:http://dx.doi.org/10.1063/1.3666260 (2 pages)

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Conventional Thermally stimulated current (TSC) studies using white light or monochromatic light LEDs cannot discriminate the electron trap from the hole trap. In order to determine the donor like or acceptor like defects, the TSC studies are carried out using the dual light illumination, namely the illumination with wavelength above or near the band gap and subsequent the illumination with wavelength below the band gap. Three broad peaks are observed using ultraviolet or blue LEDs in 30 MeV electron‐irradiated ZnO single crystals. These peaks are resolved by six traps, P1 (149 meV), P2 (256 meV), P3 (317 meV), P4 (381 meV), P5 (525 meV), and P6 (650 meV). The origin of the P2 and P3 traps has been tentatively attributed to Li acceptor and oxygen vacancy, respectively. P1, P2, and P3 traps disappear by the dual light illumination. It is suggested that P1, P2, and P3 traps are the donor like defects located near the conduction band, while P4, P5, and P6 traps are the acceptor like defect related to energy levels located near the valence band. The Li acceptor introduced during the crystal growth might be related to P4 rather than P2 traps.
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85.60.Jb Light-emitting devices
61.72.Bb Theories and models of crystal defects
71.15.Ap Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)
81.10.Aj Theory and models of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation

Evaluation of Carbon Interstitial in C‐ion Implanted ZnO Bulk Single Crystals by a Nuclear Reaction Analysis Study: An Origin of Low Resistivity

Y. Izawa, K. Matsumoto, T. Oga, K. Kuriyama, K. Kushida, and A. Kinomura

AIP Conf. Proc. 1399, pp. 69-70; doi:http://dx.doi.org/10.1063/1.3666261 (2 pages)

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Nuclear reaction analysis (NRA) of carbon‐implanted ZnO bulk single crystals (carbon concentration: 1.5×1020 cm−3), in conjunction with the channeling technique, using the 12C(d,p)13C and 16O(d,p)17O reactions shows the presence of the interstitial carbon (Ci) and the occupancy of substitute sites of oxygen atoms. These results suggest that the variation in resistivity from the order of 104 Ωcm (for un‐implanted samples) to that of 10 Ωcm (for as‐implanted ones) is attributed to the Ci and∕or its complex defects, which would act as a shallow donor in ZnO.
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61.85.+p Channeling phenomena (blocking, energy loss, etc.)
61.72.Bb Theories and models of crystal defects
61.72.jj Interstitials
25.45.De Elastic and inelastic scattering

Effect of Ultraviolet Irradiation on the Defect States and Charge Transport Properties of Low‐k SiOC(‐H) Dielectric Films Deposited by UV‐Assisted PECVD

A. S. Zakirov, R. Navamathavan, T. W. Kang, C. Y. Kim, and Chi Kyu Choi

AIP Conf. Proc. 1399, pp. 71-72; doi:http://dx.doi.org/10.1063/1.3666262 (2 pages)

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Low‐k SiOC(‐H) films with different structural orders were fabricated by using UV‐assisted PECVD, and the influence of the replacement of Si–O bonds to the (Si–R) bonds on structural and electro‐physical properties has been investigated. By analyzing the changes of the C‐V characteristics, we found that the excess –CH3 or Si–CH3 and Si‐H bonds in SiOC(‐H) films produced the effective positive charges coming from excessive interstitial defects. UV irradiation depopulates these defect states at the range of rf‐power 400–600 W. Observed shifts in the flat‐band voltage (Vfb) toward zero volts with increasing RF power indicate that positive trapped charges can be neutralized by effective negative charges coming from excessive oxygen. It was found also that the space‐charge‐limited current mechanism dominant at rf‐power below 700 W. At higher RF power and under UV irradiation, this is followed by Poole‐Frenkel emission mechanism.
Show PACS
61.72.jj Interstitials
61.72.Bb Theories and models of crystal defects
77.22.Jp Dielectric breakdown and space-charge effects
84.37.+q Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.)
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