Photoluminescence characterization of Te-doped GaSb layers grown by liquid-phase epitaxy from Bi melts

Abstract

Tellurium-doped GaSb epitaxial layers with electron concentrations in the range from - are grown at by liquid-phase epitaxy from Bi-based melts. The low-temperature photoluminescence (PL) spectra of the layers with electron concentrations above are dominated by a single broad band L1, which is attributed to a transition from the degenerated conduction band to the valence band. At electron concentrations in addition to L1 two new PL bands L2 and L3 are detected which are due to transitions of electrons to two different acceptors. In the layers grown from Bi melts, the dominant background acceptor is not the GaSb antisite-related native acceptor, but a much shallower acceptor with an ionization energy of . In addition, the layers are also free from the deep antisite complexes , which are the characteristic defects for Te-doped layers grown by liquid-phase epitaxy from Ga-rich melts, metal organic vapour phase epitaxy and molecular beam epitaxy.