Study of the optical and structural properties of multi quantum well structures grown on high-index surfaces
The MOVPE overgrowth of high [01@?1]-oriented ridges confined at sides by facets related to {n11} crystallographic planes is reported. We studied the influence of the side tilt on the thickness of the AlGaAs and GaAs epitaxial layers grown under the condition of the kinetic growth mode. The multi quantum well (MQW) structures were prepared on the sides of ridges tilted at 54.7^o, 45^o and 30^o to (100). The sidewall surface morphologies before and after epitaxial growth were evaluated and compared. We observed no tendency towards planarization towards a neighbouring high-index crystallographic plane, such as (211) and (311). We also showed that the quantum wells of the MQW structure make a smooth transition over the edge between the top surface and the facet as both AlGaAs and GaAs grew at similar rates on the surfaces.
Infrared absorption and current-voltage characteristic of GaAs/ AlGaAs multiple quantum wells on GaAs (111)A substrate grown by solid source molecular beam epitaxy
Abstract Infrared absorption and current–voltage characteristic of Si-doped GaAs/AlGaAs multiple quantum wells (MQW) grown on GaAs (1 1 1)A substrate by solid source molecular beam epitaxy has been presented in this paper. Strong polarization dependence was found and the normal incidence absorption is dominant in the (1 1 1)A-oriented MQW structure with the peak absorption wavelength around 7 μm. The final excited state is quite higher than the top of the barrier and the polarization property is complicated by the coupling between the valence heavy hole and light hole states in the continuum subband. The symmetric dark current characteristic to the zero voltage under positive and negative bias conditions attributes to the bias symmetric structures for (1 1 1)A-oriented MQW and the negligible outdiffusion of Si during the growth. The activation energies extracted from I – V characteristic curve decrease with increasing bias voltage in an exponential relation. The overall agreement between the activation energy and the calculated result has also been obtained.
Crystallographic dependence of OMVPE InGaAs/InP lateral growth on patterned (100) InP substrates prepared by wet etching
Abstract InP layers and InP/InGaAs structures were grown at 600°C using OMVPE on non-planar wet-etch InP substrates with patterns aligned at various angles Θ within [010] and [01-1] as well as [001] and [0-11]. The patterns were 15-μm-high ordinary mesa-shaped ridges with the sidewall facet angle α dependent on the alignment angle Θ. Within 0.5°