Molecular beam epitaxial growth and characterization of gallium antimonide, and its use in gallium antimonide/aluminum antimonide heterostructures

Gallium Antimonide/Aluminum Antimonide (GaSb/AlSb) quantum well structures have been grown by molecular beam epitaxy on GaAs substrates. We have obtained good quality in spite of the large lattice mismatch (7%), which results in high dislocation density.; GaSb/AlSb milti-quantum well structures have been grown by molecular beam epitaxy, with well widths from 12 to 120 A. There is a sharp drop in photoluminescence as the well width is reduced below 40 A. This is attributed to a direct-to-indirect band gap transition due to the quantum size effect. The absorption data show well-resolved light-hole and heavy-hole exciton peaks. It is found that the peak splittings obtained from absorption can be fitted by taking into account the effect of strain on the valence band in the quantum well (and barrier).; N-type and p-type modulation doped double-heterostructures have been grown. Mobility enhancement has been observed at low temperature for both p-type and n-type structures. Shubnikov-de Haas oscillations have been observed at high magnetic fields in the n-type structure, confirming the presence of a two-dimensional electron gas. Mobilities as high as 30,000 cm{dollar}sp2{dollar}/V-s have been obtained for the n-type structure.