Structure, Morphology and Photoelectric Properties of n-GaAs--p-(GaAs)1--x(Ge2)х Heterostructure

Abstract

The paper studies the structural properties of the thin-film (GaAs)1--х(Ge2)x solid solutions grown by liquid-phase epitaxy on single crystal GaAs substrates. The obtained epitaxial layers were 10 μm thick, had a 0.17 Ω · cm resistivity of p-type conductivity. X-ray diffraction analysis showed that the obtained films are monocrystalline with nanoinclusions with block sizes up to 49 nm, with a crystallographic orientation (100), and have a sphalerite structure of the ZnS type. Morphological studies using AFM showed that the nanocones on the surface of the epitaxial (GaAs)1--х(Ge2)x layers are due to Ge atoms in them. The analysis revealed that the diameter of the nanocones' bases is in the range from 70 to 90 nm, and the height is from 3 to 12 nm. The sizes of such nanocones, determined by the X-ray diffraction method, were close to these values. The photosensitivity spectra of these solid solutions exhibit peculiar fluctuations due to various complexes of charged atoms in them. Analysis of the photosensitivity spectrum of n-GaAs--p-(GaAs)1--х(Ge2)x heterostructures using the Wolfram Mathematics 7 program showed that the spectrum consists of three peaks due to As--Ge, Ge--Ge and Ga--Ge