S-Doping of MBE-GaSb with H₂S Gas

Abstract

The possibility of S-doping MBE-GaSb using H2S gas has been demonstrated. The sulfer atoms are thermally dissociated from the H2S gas, and are adsorbed at Sb vacancy sites. The S sticking coefficient depends on the Sb coverage. The electron mobility of S-doped GaSb is relatively low. This may be caused by a high compensation ratio and lattice mismatch between the GaAs substrate and the GaSb film. From the experimental results, the activation energy of the S-donor is estimated to be about 75 meV.

Brief Review of Epitaxy and Emission Properties of GaSb and Related Semiconductors

“…For samples grown using MBE technology, better crystallinity is obtained when using a growth temperature range of 500-550 • C and an Sb 4 :Ga flux ratio of more than 1.5 [34]. In another study, buffer layers were used to reduce the defect concentrations [35]. Clearly, high-quality MBE-grown GaSb, which demonstrates higher carrier mobility, can be obtained by the optimization of the growth conditions [33][34][35][36].…”

“…In another study, buffer layers were used to reduce the defect concentrations [35]. Clearly, high-quality MBE-grown GaSb, which demonstrates higher carrier mobility, can be obtained by the optimization of the growth conditions [33][34][35][36]. More importantly, PL measurements can serve to determine the transitions that occur in good quality GaSb materials [33].…”

“…From the previous section, owing to band tailoring properties of GaAsSb being important for devices with hetero-epitaxial structural designs, and particularly edge-emitting lasers [35,38] and vertical cavity surface-emitting lasers (VCSELs), many research efforts have been made in epitaxy growth of GaSb materials. In recent decades, MBE growth of GaAs 1−x Sb x over the entire composition range has been reported [39,40], and ternary compounds have been estimated using Vegard's law [41].…”

Radiative-recombination transitions in sulphur-doped GaSb

“…Reports on the successful growth of sulphur-doped GaSb crystals by epitaxial [1][2][3][4][5][6] as well as by Czochralski methods [7,8] were published by several research teams. Doping GaSb with sulphur is a technological task stimulating researchers for several reasons.…”

“…Like doping with tellurium or selenium it could provide n-type GaSb, whereas GaSb produced by standard growth techniques is usually p-type [9]. Doping with sulphur poses also some technological problems [1,2,4,8]. It is necessary to find a doping source with suitable physical properties as well as to tackle the effect of a strong sulphur volatility during the crystal growth.…”