Abstract:
Films of the solid solutions Si$_{1-x}$Sn$_x$ (0 $\le x\le$ 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 $\le x\le$ 0.04) have been analyzed. The grown epitaxial films of the solid solutions Si$_{1-x}$Sn$_x$ (0 $\le x\le$ 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 Si-SiO$_2$ 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 $\le x\le$ 0.04) are described by the exponential law $J = J_0\exp(qV/ckT)$ at low voltages ($V <$ 0.2 V) and the square law $J=(9 q\mu_p\tau_p\mu_n N_d/8d^3)V^2$ 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.
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