Strain effect in aGaAs−In0.25Ga<

Abstract

We report a theoretical investigation of the strain effects on the electronic energy band in a GaAs-In 0.25 Ga 0.75 As-Al 0.5 Ga 0.5 As asymmetric quantum wire formed in a V-grooved substrate. Our model is based on the sp 3 s* tight-binding model. It includes different spatial distributions of the lattice-mismatchinduced strain. We solve numerically the tight-binding Hamiltonian through the local Green's function from which the electronic local density of states ͑LDOS͒ is obtained. The detailed energy band structure ͑discrete localized states and energy bands of extended states͒ and the spatial distribution of the eigenfunctions ͑wave function amplitude of nondegenerate states or sum of the wave function amplitudes of degenerate states͒ are directly reflected in the LDOS. Spatial mapping of the LDOS's shows a reduction of the lowest excitation energies in different regions of the system when the local lattice structure of the In 0.25 Ga 0.75 As layer relaxes from completely strained to completely relaxed. By comparing the calculated results with photoluminescence measurement data, we conclude that the strain in the In 0.25 Ga 0.75 As layer relaxes linearly from the heterointerface with the Al 0.5 Ga 0.5 As buffer layer to the heterointerface with the top GaAs layer.

Effects of Shape and Strain Distribution of Quantum Dots on Optical Transition in the Quantum Dot Infrared Photodetectors

“…The recursion method is used to calculate the energy levels of three different shaped QDs [ 20 ]. For the experimental data, the broadening (FWHM) of the PC spectrum and the first peak of the PL spectrum are 34.01 and 29.34 meV, respectively.…”

Strain and optical transitions in InAs quantum dots on (001) GaAs

“…In the current investigation at room temperature, we simply shift down the conduction-band edge by 0.127 eV. The method has been applied to strain fields in Si-C [16] and InGaAs quantum wire [17]. As observed from Table 1, the ground transition energy in a completely strained InAs QD must be more than 1.3571 eV at low temperature and 1.2301 eV at room temperature (wavelength shorter than 1.008 µm), while for a completely relaxed InAs QD, it is only 0.4338/0.3068 eV (2.858/4.042 µm) at low/room temperature.…”

High thermal stability of photoluminescence in a disordered quantum wire superlattice

“…To realize lower-dimensional disordered structures, accurate control of the size and multilayer potential profile, i.e., energy-band-gap engineering ͑EBE͒ in more than one direction, is required. V-grooved QWRs have attracted much attention in recent years [13][14][15][16][17][18][19][20][21] due to their simplicity of fabrication and prospects on device application. 13,22,23 The V-grooved QWR is fabricated by direct epitaxial growth on a V-grooved substrate, during which the EBE can be easily realized in the growth and lateral directions.…”