Modulation spectroscopy study of the effects of growth interruptions on the interfaces of GaAsSb/GaAs multiple quantum wells

Abstract

The effects of growth interruption times combined with Sb exposure of GaAsSb/GaAs multiple quantum wells (MQWs) have been investigated by using phototransmittance (PT), contactless electroreflectance (CER) and wavelength modulated surface photovoltage spectroscopy (WMSPS). The features originated from different portions of the samples, including interband transitions of MQWs, interfaces and GaAs, are observed and identified through a detailed comparison of the obtained spectra and theoretical calculation. A red-shift of the interband transitions and a broader lineshape of the fundamental transition are observed from samples grown under Sb exposure compared to the reference sample grown without interruption. The results can be interpreted in terms of both increases in Sb content and mixing of Sb in the GaAs interface layers. An additional feature has been observed below the GaAs region in the samples with Sb treatment. The probable origin of this additional feature is discussed.

Effect of exciton transfer on recombination dynamics in vertically nonuniform GaAsSb epilayers

“…In contrast to conventional III-III'-V alloy systems such as AlGaAs, strong competition between two group-V elements in GaAsSb leads to their non-unity sticking coefficients, which complicates the incorporation behavior of Sb and As atoms. 10,11 It was shown that a naturally formed Sb gradients exists in GaAsSb epitaxial layers grown by molecular beam epitaxy (MBE). 12 Moreover, a consistent self-induced Sb compositional gradients are also observed in GaAsSb nanowires grown by MBE, leading to a specific and reproducible rectifying behavior.…”

Investigation of Localized Electric Field in the Type-II InAs/GaAsSb/GaAs Structure

“…The period of FKO is known to be strongly related to the built-in electric field of semiconductors and their heterostructures. The electric field is proportional to the period of FKO [10]. However, in this structure, we cannot expect any built-in electric field because these structures are composed of only undoped layers.…”

Growth interruption strategies for interface optimization in GaAsSb/GaAsN type-II superlattices

“…To reduce the compositional gradient not only at the start of the Sb layer but also at the final interface, different growth approaches have been proposed. On the one hand, applying different growth interruption (GI) times with Sb exposure ("soaking") prior to the growth of a new Sb-containing layer has been associated with better structural quality and higher Sb incorporation [18][19][20], which leads to better optical performances [21,22]. In general, antimonides present weaker bonds compared to arsenides, so the As-for-Sb exchange is energetically favorable, leading to slower incorporation of Sb atoms into epitaxies with simultaneous As deposition [23].…”