SWIR Photosensory

In this paper, we report on the design, the fabrication, and performance of SWIR photomodules using sensitive two-dimensional arrays based on InGaAs-heterostructures. The de- sign of suggested InGaAs-heterostructure includes InAlAs wideband barrier layer and high sensitive absorber InGaAs layer which are increasing the uniformity and operability of focal plane array (FPA), so the number of defect elements are less than 0.5 %. The possibilities of spectral range expanding into short-wavelength to 0.5 μm and into long-wavelength to 2.2 μm regions have been considered. The operation principals of active-pulse system for 0.9–1.7 μm spectral range based on InGaAs 320256 FPA with 30 μm pitch have been presented. The investigations showed that the infrared gated-viewing system based on the InGaAs 320256 FPA provided a spatial resolution of 0,6 m.

Enhanced Properties of Extended Wavelength InGaAs on Compositionally Undulating Step-Graded InAsP Buffers Grown by Molecular Beam Epitaxy

The extended wavelength InGaAs material (2.3 μm) was prepared by introducing compositionally undulating step-graded InAsyP1−y buffers with unequal layer thickness grown by solid-source molecular beam epitaxy (MBE). The properties of the extended wavelength InGaAs layer were investigated. The surface showed ordered crosshatch morphology and a low roughness of 1.38 nm. Full relaxation, steep interface and less than one threading dislocation in the InGaAs layer were demonstrated by taking advantage of the strain compensation mechanism. Room temperature photoluminescence (PL) exhibited remarkable intensity attributed to the lower density of deep non-radiative centers. The emission peak energy with varied temperatures was in good agreement with Varshni’s empirical equation, implying high crystal quality without inhomogeneity-induced localized states. Therefore, our work shows that compositionally undulating step-graded InAsP buffers with a thinner bottom modulation layer, grown by molecular beam epitaxy, is an effective approach to prepare InGaAs materials with wavelengths longer than 2.0 μm and to break the lattice limitation on the materials with even larger mismatch.

Исследование элементарных процессов МOC-гидридной эпитаксии наногетероструктур на основе арсенида галлия методом атомно-силовой микроскопии

Using atomic force microscopy, we studied the elementary processes of growing (Al, Ga, In) As heterostructures on misoriented GaAs (001) substrates by the method of MOC hydride epitaxy under reduced pressure. It was established that the growth of the epitaxial layers of GaAs and AlGaAs occurs according to a layered mechanism with the formation of macrosteps. The growth of pseudomorphic InGaAs / GaAs (001) layers also occurs by a layered mechanism with the formation of macrosteps. However, if the thickness of the pseudomorphic InxGa1-xAs / GaAs (001) layer exceeds a certain critical value depending on the molar fraction of InAs in the composition of the solid solution (x), the formation of growth defects in the form of three-dimensional islands, the density of which increases with increasing thickness, is observed on the surface of the InGaAs layer InGaAs layer. The formation of three-dimensional InGaAs islands is associated with the relaxation of elastic stresses in the pseudomorphic InGaAs / GaAs (001) layer according to the Stranski-Krastanov mechanism. Keywords: gallium arsenide, AlGaAs, InGaAs, MOC hydride epitaxy, defect formation, Stranski-Krastanov mechanism.