Impurities in type-II-staggered InAs/AℓSb superlattices

✍ Scribed by John D. Dow; Jun Shen; Shang Yuan Ren

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 314 KB
• Volume: 13
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1993.1080

✦ Synopsis

The physics of impurities in Type-II staggered superlattices is reviewed, with emphasis on changes of doping character, such as shallow to deep and deep to falsevalence transitions, that can result from altering layer thicknesses. It is shown how some impurities can change their doping characters from "deep acceptors" (semi-insulating) to shallow donors (n-type) as functions of layer thicknesses in superlattices such as (\operatorname{In} A s / A \ell S b). A particularly important case is an (\mathrm{A}_{\mathrm{Sb}}) antisite defect in an (\mathrm{A} \ell \mathrm{Sb}) layer of an (\operatorname{In} \mathrm{As} / \mathrm{A} \ell \mathrm{Sb}) superlattice. This defect is a deep trap or "deep acceptor" in (\mathrm{A} \ell \mathrm{Sb}), and a remote donor in some superlattices, depending on the layer thicknesses. It can, by itself, control the electron gas density in a superlattice structure, and so can play an important role in the development of high-speed field-effect transistors.