Electron diffraction study of photosensitive heterostructures PbSnTe-PbTe grown by MBE

摘要

Electron diffraction study of PbTe and PbSnTe epitaxial layer surface and heterojunctions on their bases grown by MBE on mica was carried out. The aim of this study was determination of correlation between diffusion streaks intensity on diffraction patterns and photoelectric parameters of p-n junctions made in these structures. The diffusion streaks intensity depends on thickness and temperature of layers growing. More pronounced streaks on electron diffraction patterns are observed from thicker layers (d>1μm) grown at higher temperatures (>300°C). Diffusion streaks intensity of heterolayers PbSnTe-PbTe grown at 380-400°C changes most heavily at changing film thickness from tenth fractions of micron till ≈ 1μm. At further increase of film thickness till ≈ 4-5 μm diffusion streaks intensity changes slightly. Peak of heteroj unction Pb_(1-x)Sn_xTe-PbTe (x= 0.2) photoresponsivity grown at 380-400°C at film thickness 0.5-1 μm locates at 4.5 μm with sloping decreasing till 6 μm. Het-erojunction with same composition grown at same temperature with film thickness 4-5μm has peak of photoresponsivity at 8.5 μm. The correlation between diffusion streaks intensity and photoelectric parameters of film p-n structures is found out.