Self-Organized Superlattices in GaInAsSb Grown on Vicinal Substrates

Wang, C.A. ; Vineis, C.J. ; Calawa, D.R.

Lockheed Martin

关键词: Alloys;    Superlattices;    Modulation;    42 Engineering;    Deposition;   

DOI  :  10.2172/822275
RP-ID  :  LM-03K116
RP-ID  :  AC12-00SN39357
RP-ID  :  822275

美国|英语

来源: UNT Digital Library

【 摘 要 】

Self-organized superlattices are observed in GaInAsSb epilayers grown lattice matched to vicinal GaSb substrates. The natural superlattice (NSL) is oriented at a slight angle of about 4{sup o} with respect to the vicinal (001) GaSb substrate. This vertical composition modulation is detected at the onset of growth. Layers in the NSL are continuous over the lateral extent of the substrate. Furthermore, the NSL persists throughout several microns of deposition. The NSLs have a period ranging from 10 to 30 nm, which is dependent on deposition temperature and GaInAsSb alloy composition. While the principle driving force for this type of phase separation is chemical, the mechanism for the self-organized microstructure is related to local strains associated with surface undulations. By using a substrate with surface undulations, the tilted NSL can be induced in layers with alloy compositions that normally do not exhibit this self-organized microstructure under typical growth conditions. These results underscore the complex interactions between compositional and morphological perturbations.