Investigation of the transport properties of InSb single-crystal films obtained by directional crystallization

Abstract

Both n-type and p-type InSb films (with a wide range of carrier concentration) were obtained by the directional crystallization method from the melt on large areas of mica, quartz and sapphire substrates. The p-type films were doped with germanium. It is shown that, depending on the crystallization conditions, one can obtain films of different structure: dendritic films, films containing macrodefects and homogeneous single-crystal films. The optimal growth conditions of single-crystal films having transport properties close to those of bulk material are given. The investigation of some transport properties in single-crystal p-type InSb films was carried out in the temperature range 77–600 K. A hole mobility in the range from 180 cm 2 V -1 s -1 to 5×10 3 cm 2 V -1 s -1 in films with a concentration p=1.2×10 16−5×10 18 cm -3 of uncompensated acceptors was observed. An investigation of the concentration and temperature dependence of the hole mobility was carried out. Experimental results are in good agreement with the theory if a combined impurity, acoustic and optical mode scattering is taken into account. The phonon drag effect in p-type InSb films was observed. The temperature dependence of the thermoelectric power shows fair agreement with Herring's theory.