Growing Ge1-xSnx solid solutions on Ge, GaAs substrates

Single-crystal films of the Ge1-xSnx solid solution were grown in the temperature range of 893-723 K at a cooling rate of 0.5-1.5 K/min from a limited tin solution-melt. The substrates were Ge(111) and GaAs(100) with a carrier concentration of n=(1÷5)·1017cm–3, n=(4÷7)·1017cm-3, respectively. The gap between the substrates was 0.65÷1.2 mm. The technological conditions for obtaining a GaAs- Ge1-xSnx heterostructure with a smooth substrate-film boundary were achieved, while the supercooling temperature was T=6.2 °C. The single crystallinity of the Ge1-xSnx 0 ≤ x ≤0.03) film was determined by X-ray diffractometry. The film photosensitivity covers the spectral region of 0.5-1.9 eV.