Hall effect and resistivity in liquid-phase-epitaxial layers of HgCdTe

Abstract

The Hall effect and resistivity have been measured in liquid-phase-epitaxial (LPE) HgCdTe layers in the temperature range between 16 and 300 K. The composition of the material covers the wavelength range from 3 to 12 μm. The results obtained from a broad sample base have been systematically analyzed and categorized. Although much of the data follows classical behavior and is readily understood, it has now become possible to analyze quantitatively the variety of other observed Hall-effect data in some of the LPE HgCdTe layers by making use of a theoretical model for multilayer structure. This allows such fundamental properties as surface charge density, bulk carrier concentration, surface and bulk mobility, and dopant concentration in double-layer heterojunctions to be extracted from the experimental data otherwise classified as ‘‘anomalous’’ and not analyzable previously. Controlled experiments have been carried out to show the dependence of Hall-effect measurements on layer thicknesses and various surface conditions. Evidences are described that identify three types of structure that produce the observed anomalous data: n skin on p layer, n layer on p layer, and n skin on n layer. The layer model is outlined, emphasizing its development for application to LPE HgCdTe. The temperature-dependent mobilities of both electrons and holes required in the model are derived from the large data base. Allowance is also made for the magnetic-field dependence of the measured Hall coefficient.