Structural and some electrophysical properties of the solid solutions Si_{1 − x} Sn _x (0 ≤ x ≤ 0.04)

Abstract

Films of the solid solutions Si_{1 − x} Sn _x (0 ≤ x ≤ 0.04) on Si substrates have been grown by liquid phase epitaxy. The structural features of the films have been investigated using X-ray diffraction. The temperature behavior of current-voltage characteristics and the spectral dependence of the photocurrent for the heterostructures p-Si-n-Si_{1 − x} Sn _x (0 ≤ x ≤ 0.04) have been analyzed. The grown epitaxial films of the solid solutions Si_{1 − x} Sn _x (0 ≤ x ≤ 0.04) have a perfect single-crystal structure with a (111) orientation and a subgrain size of 60 nm. In the epitaxial films at the Si-SiO₂ interfaces between silicon subgrains and SiO₂ nanocrystals, where there are many sites with a high potential, the Sn ions with a high probability substitute for the Si ions and encourage the formation of Sn nanocrystals with different orientations and, as follows from the analysis of the X-ray diffraction patterns, with different sizes: 8 nm (for the (101) orientation) and 12 nm (for the (200) orientation). The current-voltage characteristics of the heterostructures p-Si-n-Si_{1 − x} Sn _x (0 ≤ x ≤ 0.04) are described by the exponential law J = J ₀exp(qV/ckT) at low voltages (V < 0.2 V) and the square law J = (9qμ _p τ _p μ _n N _d /8d ³)V ² at high voltages (V > 1 V). These results have been explained by the drift mechanism of charge carrier transport in the electrical resistance relaxation mode.