Effects of indium doping on the properties of AlAs/GaAs quantum wells and inverted AlGaAs/GaAs two-dimensional electron gas

Abstract

The effects of indium doping on the optical properties of AlAs/GaAs quantum wells (QWs) and the electrical properties of inverted AlGaAs/GaAs two-dimensional electron gas (2DEG) were investigated. It is found that incorporation of a small amount of In in AlAs layers can decrease the photoluminescence linewidths of AlAs/GaAs QWs drastically and a small amount of In doping in AlGaAs layers can increase significantly the electron mobilities of inverted AlGaAs/GaAs 2DEG at 77 K. All these results demonstrate that In doping can improve the interface roughness because In as a surfactant can enhance the surface migration of Al adatoms during molecular beam epitaxy.

Optical properties of AlAs/GaAs quantum wells with antimony as a surfactant by solid source molecular beam epitaxy

“…It is clearly shown that the incorporation of very small amounts of Sb doping greatly improves the interface quality of AlAs/GaAs MOWs. Due to the relatively weaker bond of AlSb than that of AlAs, it may decrease the surface free energy of Al and result in enhanced Al diffusion [4][5][6][7]. Sb at the surface preferentially occupies those more stable sites at the step edges, and by changing the local energy configuration facilitates the descent of Al down the sites [5].…”

“…Sb at the surface preferentially occupies those more stable sites at the step edges, and by changing the local energy configuration facilitates the descent of Al down the sites [5]. As the quality of the surface (interface) is controlled by cation migration, this would lead to a smooth interface [5,6,17]. Fig.…”

“…The surfactant strongly affects surface properties, such as surface energy, surface diffusion and surface morphology [3]. Due to the high Al-As bond strength, which reduces the surface mobility of Al, Sb as a surfactant has successfully been made to reduce the surface free energy, and hence enhance the surface migration of cation Al adatoms and has been used to improve the interfacial and crystalline quality in aluminium-containing material growth [4][5][6][7]. The interface quality plays an important role in the optical and electronic properties of devices such as vertical-cavity surface-emitting lasers (VCSELs) [8], quantum well lasers [9], high electron mobility transistors [10], and resonant tunneling diodes [11].…”

Influence of interface interruption on spin relaxation in GaAs (110) quantum wells

“…One reason for the asymmetry is the lower Al mobility on the Al x Ga 1Àx As surface during growth which gives rise to a higher degree of interface roughness [18]. Growth interruption at the heterointerfaces allows for the redistribution of cations at the growth front, which, in turn, results in a significant smoothing of the interface profile [19]. In MBE, a growth interruption at the interface has proven to be very efficient for obtaining large atomically smooth interfaces [20].…”

Модификация поверхности GaAs и наблюдение эффекта гигантского рамановского рассеяния после диффузии индия

“…Например, было показано, что присутствие индия в процессе роста слоев AlGaAs существенно улучшает со-стояние гетерограницы GaAs/AlAs. Это, в свою очередь, увеличивает подвижность электронов в AlGaAs/GaAs I-HEMT [6].…”