O.P. Taneja

Electrical transport properties of p-type Pb1−xCdxS epitaxial thin films

Abstract Measurements were made of the Hall coefficient and d.c. conductivity of p-type Pb 1− x Cd x S thin films grown on mica substrates. It was found that films with x x ≈ 0.1 is comparable with that in films grown on other substrates, e.g. NaCl and BaF 2 .

Field effect studies in p‐type InSb MIS structures

Field effect studies on MIS structures of silver‐glass p‐type InSb have been made in the temperature range 77–300 K. It has been observed that the effect of negative gate voltage is to decrease the Hall coefficient, Hall mobility, and grain boundary barrier potential, while the effect of positive gate voltage is opposite but less significant. The results can be explained in terms of accumulation and depletion layers, induced on the surface.

The electrical effect of hydrogen on InSb films

Polycrystalline films of n‐InSb were exposed to hydrogen at 300 and 500 psi for 2 h. Large changes were observed in the Hall coefficient and mobility, denoting a transfer of donor states to the films. This is believed to involve the in‐diffusion of hydrogen, which was found to be irreversible within a period of one month.

Some leakage current observations on anodic native oxides on GaAs

Leakage current measurements across MOS diodes with native electrolytic nsidesevhibit a behaviour which is tentatively explained on the basis of the effect of non-oxidized As traps near the interface in the oxide,

Electrical effects of thallium on the Hall mobility in p-PbTe thin films

Abstract The Hall coefficient and Hall mobility were measured for epitaxial p-type PbTe films doped with thallium. It was observed that doping of the films with thallium leads to a decrease in the mobility and an increase in the concentration of charge carriers. The mobility μD limited by defect scattering was calculated and was found to be independent of temperature and to decrease with increases in the carrier concentration p. For films with carrier concentrations exceeding 7 × 1018 cm-3 the value of μD decreases as p- 4 3 , whereas for films with lower carrier concentrations the decrease in μD with p is at a slower rate.

Electrical effects of thallium, sodium and silver impurities on lead telluride thin films

Abstract Thin epitaxial films of PbTe incorporating Ag and Tl impurities were deposited by coevaporating these elements with PbTe from two separate boats onto heated mica and sapphire. Na doped films were prepared by coevaporating NaCl and PbTe. The rates of the various constituents were carefully monitored in order to have a wide concentration range. DC conductivity and Hall measurements have been reported on these films in the temperature range of 100–700 K. Various band parameters, i.e. mobility, effective mass and population ratios for light and heavy holes, have been estimated as a function of carrier concentration and temperature on the basis of a two-valence band model. All these impurities have been found to give p-type behaviour. For a given carrier concentration, the mobility ratio of light to heavy holes ( b= μ 1 μ h ) for Ag doped films was larger as compared to those doped with Na and Tl. It has been observed that the values of b for all these films decrease with increasing carrier concentration. However, this decrease is smaller in the case of Tl and Na doped films than in Ag doped films. The effect of various dopants on the valence band separation (ΔEv) has been found to be almost independent of dopant and its concentration. The Hall mobility has been observed to decrease with increasing carrier concentration. Data on the variation of the mobility temperature have been found and were analysed in terms of different scattering mechanisms.

Electrical transport properties of hydrogen-exposed p-type PbTe films

Abstract Hall coefficient and d.c. conductivity measurements were made on p-type PbTe epitaxial films exposed to molecular hydrogen gas at high pressures (100–500 psi) in the temperature range (100–300K). It is found that hydrogen converts p-type films to n-type at a pressure of about 300 psi. The results are explained by assuming that the action of hydrogen is to provide donor electrons.

The effect of hydrogen on the electrical properties of p-type PbTe epitaxial films

Abstract Measurements of the Hall coefficient and the d.c. conductivity of p-type epitaxial PbTe films exposed to hydrogen gas at high pressures were carried out. It was observed that hydrogen gas exerts compensating effects in the films at low pressures, while at high pressures (exceeding 225 lbf in-2) it provides donor electrons.

Electrical transport properties of hydrogen-exposed n-type InSb films

Abstract Hall coefficients and d.c. conductivities were measured for polycrystalline n-type InSb films exposed to H 2 gas at different pressures. It was found that H 2 gas molecules act as donor impurities for the films and the donor action increases with increasing pressure of the gas. The mobility, however, was found to decrease, showing the increasing contribution of ionized impurity scattering with increasing pressure of the gas.

Electrical transport properties of p‐type Pb1−xCdxTe thin films

Hall coefficient and dc conductivity measurements have been made in the temperature range 77–500 K on thin exptaxial films of p‐type Pb1‐xCd xTe, grown by vacuum evaporation using a three‐temperature technique. It has been found that the principal band gap and the mobility ratio of electron to hole increases with the increase of x. Increase of x is found to increase Te vacancies in the films which act as donors. In the low‐temperature region, the ionised impurity scattering is found to be predominant, while the phonon scattering is found to limit the mobility of the charge carries at higher temperatures.