INVESTIGATION OF ION-IMPLANTED PbTe SEMICONDUCTOR FILMS WITH ARGON IONS

Abstract

PbTe semiconductor films were obtained by discrete evaporation and were block single crystals oriented with the “///” axis perpendicular to the layer plane. The method of discrete evaporation together with steam homogenization made it possible to reproduce the composition of the charge in the condensate and minimize the loss of volatile components. This technology, which we have chosen, is relatively simple and provides high performance. This gave us the opportunity to exclude a number of issues related to the difference in technology when discussing the impact of ion implantation.

To measure the complex of kinetic coefficients in films, an experimental setup was created.  The setup made it possible to measure the coefficients of resistivity (ρ), Hall (R), Seebeck (α), and Nernst-Ettingshausen transverse effect (Q). These effects were measured on almost all samples. In addition, if necessary, we were able to measure the change in resistance and thermoelectric power in a magnetic field. Sample temperature range 77….330K, magnetic field – up to 1.5 Ts, semiconductor film thickness d ≃ 0.35...0.55 µm.

Studies on a scanning electron microscope made it possible to determine the average size of blocks ~ 10-1 μm. The freshly deposited layers had both n- and r - type. It should be noted that their properties have changed over time. Layer annealing at T = 580….630K for 30 min in a helium atmosphere stabilized the properties of the samples. After annealing, the overwhelming majority of films acquired P-type conductivity and had a Hall concentration of (0.4...2) 10¹⁸ cm^-3.

The Hall mobilities at Т = 300K were (500….900) cm²/V·С.