Surfactant-Mediated Growth of Aigaas by Molecular Beam Epitaxy

Abstract

Antimony was used as a surfactant during solid-source molecular beam epitaxy of AIGaAs layers. A steady-state surface-segregated population of Sb was maintained at the AIGaAs growth surface by providing a continuous Sb2 flux to compensate for loss due to thermal desorption. Above ∼ 650 °C, the incorporation rate of Sb was negligible, thereby allowing the deposition of AlGaAs layers despite the presence of Sb at the surface. A significant improvement in the optical quality of Al0.24Ga0 76As layers was observed by photoluminescence. In addition, extended reflection high energy electron diffraction oscillations and a reduction in Al0.24Ga0.76As surface roughness was observed when Sb was employed as a surfactant.

Determination and improvement of spontaneous emission quantum efficiency in GaAs/AlGaAs heterostructures grown by molecular beam epitaxy

“…(13) and are given in Table 3. The SRH coefficients for Sample 1 (with Sb surfactant) are approximately one half of those of Sample 2 (without Sb surfactant).…”

“…Furthermore it is important to develop growth techniques that improve the quality of the III-V semiconductor materials, such as Sb mediated growth, which has been shown to improve the morphology and electrical properties of Si-doped AlGaAs [11]. Although the benefits of surfactant mediated growth have been known for sometime [12,13], its effect on the optical properties of III-V materials has not been well quantified. In this work, a straightforward experimental approach is presented for the determination of the injection dependent spontaneous emission quantum efficiency and the nonradiative recombination coefficients.…”

Growth of InxGa1−xAs/GaAs heterostructures using Bi as a surfactant

“…Indeed, they suggest an improvement in the quality of the layers. An increase in PL intensity was also observed in the case of an AlGaAs/GaAs system using Sb as a surfactant, 10 which was attributed to Sb incorporation at defects, thereby eliminating traps. Another possibility is that the Bi-covered surface was less reactive with MBE chamber background contaminants, thereby reducing the background impurity concentration.…”

“…10 Recent data for metal epitaxy provide some insight into the mechanisms by which surfactants alter growth kinetics. Longer-lived RHEED oscillations generally indicate a greater tendency for each layer to be completed prior to nucleating two-dimensional ͑2D͒ islands on the next layer.…”

“…Another possibility is the addition of a controlled amount of a group-V species. The effectiveness of this has been demonstrated in the AlGaAs/GaAs system, 10 where an adsorbed Sb surface layer was shown to improve reflection high-energy electron diffraction ͑RHEED͒ oscillations, indicating improved layer-by-layer growth, and yielded improved-quality photoluminescence peaks. Fundamental studies on metallic surfaces indicate that surfactants alter surface diffusion rates and step-attachment kinetics, 11 both of which have a strong influence on growth morphology and segregation.…”