The photoelectric properties of polycrystalline films of gallium arsenide

Certain photoelectric properties of polycrystalline films of gallium arsenide at room temperature obtained by a gas deposition method are studied. It is found that film specimens of GaAs have much greater photosensitivity than the solid material for the same current carrier density.The barrier theory of conductivity is invoked in order to explain the relationships observed.     

Investigation of the electrical and photoelectric properties of manganese-doped gallium arsenide as a material for photoresistive detectors

An investigation was made into the electrical and photoelectric properties of gallium arsenide with an initial electron density 5×10¹⁵–4×10¹⁷ cm^–3 doped with Mn in different thermodynamic diffusion regimes characterized by diffusion temperatures of 900 and 1000°C and arsenic vapor pressure 10^–2 and 10^–3 atm. The ionization energy and defect concentration were determined by a computer analysis of the equilibrium hole density determined from the Hall effect. Centers with ionization energy 0.08–0.10 eV were found, their concentration varying from 2×10¹⁹ to 2×10²⁰ cm^–3 depending on the diffusion temperature and the doping level of the original crystals. Data obtained by investigating the stationary intrinsic photoconductivity were used to determine a hole lifetime of t_p 10^–9 sec. The photoconductivity spectra were investigated in the range 0.5–2 eV at 77°K, and defects with ionization energy E_v + 0.6 eV were found in all samples. The impurity photoconductivity at wavelength 10.6 m was investigated. It was shown that GaAsMn can be used as a material for impurity photoresistors.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 15–19, March, 1981.     

Optical properties of laser-type gallium arsenide

Measurements of the optical properties of laser-type Ga As indicate a peak in the refractive index at the absorption edge frequency. The magnitude of the peak decreases as the doping levels are increased and the slope of the absorption edge decreases.     

Electrophysical properties of heat-treated gallium arsenide

The electrical conductivity, Hall effect, ionization energy, and defect concentration of GaAs samples subjected to various forms of heat treatment were studied. The original material comprised single crystals grown by the Bridgman and Czochralski methods with electron concentrations of 2·10¹⁵–7·10¹⁷ cm^–3. The ionization energy and defect concentration were calculated with an electronic computer. The thermal conversion of GaAs was attributed to traces of copper, lattice defects, and residual impurities. The mobility varied in a complicated manner with the temperature of heat treatment in GaAs samples retaining their original n-type conductivity.Translated from Izvestiya VU Z, Fizika, No. 3, pp. 69–76, March, 1973.     

Physical properties of hydrogenated amorphous gallium arsenide

Summary The elemental composition and the optical properties of hydrogenated amorphous GaAs prepared by r.f. reactive sputtering at different hydrogen and argon pressure and substrate temperature have been determined. From the dependence of the absorption coefficient on photon energy the optical gap has been deduced according to the Tauc law. The data obtained for stoichiometric samples are compared with similar data obtained by different authors. The influence of various deposition parameters on stoichiometry and on the optical properties is briefly discussed.     

Investigation of the electrophysical and photoelectric properties of diffused layers of gallium arsenide obtained by compensation of copper

The distribution of the electrophysical and photoelectric properties of diffuse layers of p-GaAs obtained by doping copper using different diffusion modes is investigated. The properties of diffuse layers of p — n structures and volume specimens doped with copper over the whole depth are compared. The behavior of impurity centers is studied in these specimens and their effect on the electrophysical and photoelectric parameters of the material is investigated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 95–100, October, 1977.In conclusion we thank I. V. Kamenskii for carrying out the experiments.     

Electronic-transport properties of unhydrogenated amorphous gallium arsenide

Summary Hall mobility, μ_H, and electrical conductivity, σ, of unhydrogenated amorphous-gallium-arsenide films, prepared by r.f. sputtering, have been measured. Conductivity as a function of temperature shows a variable-range hopping mechanism atT<260 K, while at high temperature, conductivity and Hall mobility are both thermally activated. The results are interpreted in terms of the presence of defect complexes due to an excess of Ga. The stoichiometry and the structure of the films are used to explain the behaviour and the values of μ_H. The values of the activation energy of the conductivity seem in agreement with theoretical calculations on the position of electronic states created by defect complexes in the mobility-gap of a-GaAs.     

Effect of hydrogen on the photoelectric properties of palladium/anodic oxide/gallium arsenide Schottky diodes

The effect of hydrogen on the photovoltage and I-V characteristics of palladium/anodic oxide/gallium arsenide Schottky diodes is studied. The oxide thickness that is optimal in terms of the hydrogen sensitivity of the diodes and the depth of atomic hydrogen penetration into the oxide are determined. The mechanism behind the hydrogen effect consists in the chemical adsorption of atomic hydrogen on the gallium arsenide surface, which decreases the barrier height and increases the recombination component of the current. It is shown that a thin tunnel-transparent anodic oxide film is nonuniform in thickness and that hydrogen exposure raises the probability of tunneling through the oxide. It is found that the method of hydrogen detection from the photovoltage response offers a higher sensitivity and detectivity but has a lower speed than the reverse current method.     

Preparation and electrical properties of copper-doped cadmium telluride single crystals

Preparation and the electrical properties of copper-doped cadmium telluride single crystals prepared by directional freezing and by diffusion of copper from a layer of Cu₂ Te are described in this paper. The dependence of electrical properties on the preparation mode is followed. In the enclosed infra-red spectra it is proved that samples suitable for optical measurements can be prepared by both described techniques.     

Salient features of the electrical characteristics of oxygen-implanted gallium arsenide Schottky-barrier structures

We have studied the deep levels in gallium arsenide implanted with oxygen ions at a low dose of 2·10¹⁰ cm⁻² and the influence of those levels on the current-voltage characteristics of Ni/Pd/Ga Schottky-barrier structures. The deep levels were checked by the thermally-stimulated-current (TSC) method. The number of peaks on the TSC curves and their amplitudes are shown to depend on the oxygen-ion energy and the temperature of the post-implantation anneal. An important role in the formation of centers associated with oxygen is played by gallium diffusion into the protective SiO₂/Si₃N₄ insulator layer as well as by elastic and plastic strain phenomena that occur during deposition of the coating and post-implantation annealing of the specimens. The deep levels due to oxygen are responsible for the appearance of excess currents resulting from recombination as well as for ohmic leakages. V. D. Kuznetsov Siberian Physicotechnical Institute at Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 30–36, May, 1996.     

Effect of structural changes on dielectric properties of gallium arsenide

Temperature and frequency dependence of dielectric permittivity and tangent of the dielectric loss angle are studied in epitaxial gallium arsenide structures. It is shown that nonmonotonic change in with temperature is caused by change in the volume of conductive gallium microinclusions and a difference between the structural perfection of the layer and substrate. The space charge relaxation time on inhomogeneities is evaluated (10^–5–10^–6 sec) and its contribution to GaAs dielectric properties is evaluated. An oscillation in dielectric permittivity upon heating is observed and explained.Deceased.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 18–21, February, 1989.     

Electrophysical properties of epitaxial gallium arsenide doped with acceptor impurities

Epitaxial layers of gallium arsenide doped with zinc and cadmium were grown in a chloride vapor-transport system using diethylzinc and dimethylcadmium as the sources of the impurity. We studied the effect of the inlet pressure of the impurities and the growth temperature on the doping level of the layers. We investigated the temperature dependences of the hole concentration and mobility in layers doped with zinc and cadmium up to different levels.V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 54–58, February, 1995.