Photoluminescence of strained-layer superlattices

The strained-layer superlattices (SLS's) of In_xGa_1?xAsGaAs and the single hetero-structure of In_xGa_1?xAs on GaAs were grown by MBE method. The samples obtained have a perfect surface morphology. The alloy composition of In_xGa_1?xAs layer and the growth rate were determined with high accuracy by in situ observation of the intensity oscillation of RHEED pattern. Photoluminescence peak energies of SLS's are in agreement with the calculated value by the Kronig-Penny analysis.     

ZnSe—ZnTe应变层超晶格的光吸收研究

在室温下测量了Znse-ZnTe应变层超晶格的光吸收谱,观测到对应于第一轻重空穴跃迁的吸收台阶.根据测量所得的超晶格带隙确定了ZnSe-ZnTe的价带不连续为1.10eV.     

Piezobirefringence in GaP and InP

We report measurements of piezobirefringence in GaP and InP in the region below the direct gap. For GaP this includes the region above the indirect gap where the sample is opaque. The experimental data are compared with theoretical calculations of the contributions to the piezobirefringence arising from the E₀, E₁ and E₂ transitions.     

Origin of antimony segregation in GaInSb/InAs strained-layer superlattices

We show how cross-sectional scanning tunneling microscopy may be used to reconstruct the Sb segregation profiles in GaInSb /InAs strained-layer superlattices. These profiles are accurately described by a one-dimensional model parametrizing the spatial evolution of an Sb seed at the InAs-on-GaInSb interface in terms of two-anion-layer exchange. We argue that the segregation seed, which decreases from 2 / 3 to 1 / 2 monolayer when growth conditions are made less anion rich, has its origin in the Sb-bilayer reconstruction maintained during GaInSb epitaxy.     

Photoluminescence of strained-layer superlattices under high excitations

Photoluminescence and laser oscillation from In_0.2Ga_0.8As/GaAs strained-layer superlattices were measured under pulse-light excitations. Double-peak spectra were obtained, in contrast to the lattice-matched super-lattices.     

Two-phonon absorption in InP and GaP

Far-infrared absorption in crystals of GaP and InP was investigated using a high-resolution Fourier-transform spectrometer. The two-phonon absorption was found to be very similar in these two materials. Van Hove singularities on the GaP spectrum were identified with the aid of calculated two-phonon sum and overtone density-of-states curves. The analysis of the InP spectrum was based on its homology to GaP. Many of the prominent features of the absorption spectra are assigned to pairs of phonons on the hexagonal face of the Brillouin zone while phonon pairs at Γ, X and L generally contribute only minor features to the spectra.     

ESR assessment of 3d7 transition metal impurity states in GaP,GaAs and InP

Photo-sensitive electron spin resonance of the 3d⁷-ions Fe⁺, Co²⁺, Ni³⁺ has been detected and analysed in GaP, GaAs and InP. For GaP : Ni³⁺, hyperfine interaction with the four nearest P³¹-ligands could be resolved.