Origin of the photoluminescence line at 0.8 eV in undoped and Si-doped GaSb grown by MOVPE

Abstract

We study the low-temperature photoluminescence (PL) of unintentionally doped and Si-doped bulk GaSb grown by low-pressure metal-organic vapour phase epitaxy (MOVPE) from triethylgallium (TEGa), trimethylantimony (TMSb) and silane (SiH 4 ). The background doping with Si in nominally undoped layers is shown to be caused by the TMSb precursor. Intentional Si-doping using silane results in p-doping, a reduction of the material compensation, a substantial decrease in the native acceptor concentration and a dramatic gain in the integral PL intensity compared to unintentionally doped samples. These findings suggest that the Si atoms are incorporated predominantly in the anionic sublattice. The Si-related PL line with a maximum at 0.8 eV observed in the PL spectra of both types of samples at helium temperatures is identified as a transition of a free electron to a neutral acceptor Si Sb with an activation energy of ≈9 meV. The PL spectra of GaSb layers with acceptor concentrations approaching 1 × 10 17 cm −3 , and particularly the 'blueshift' of the peak at 0.800 eV with the temperature rise, can be understood by taking into account the impact of large-scale fluctuations in the charged impurity concentration. The established properties of low-pressure MOVPE-grown Si-doped GaSb are promising for the applicability of this material to GaSb-based devices.

Photoluminescence studies on Al and Ga interdiffusion across (Al,Ga)Sb∕GaSb quantum well interfaces

“…3͑b͒, the peaks at lower energy, ϳ 1551 and 1598 nm, are attributed to substrate band-to-band recombination ͑1551 nm͒ and to transitions of free electrons to neutral native acceptors ͑1598 nm͒. 30 Agert et al have also attributed the 1551-nm PL peak to transitions of free electrons to unspecified neutral acceptors, and have reported this wavelength for recombination of excitons bound to an unspecified acceptor for Si-doped GaSb spectra taken at 4.2 K. 30 However, the data presented here were observed at 77 K, at which the probability of having significant excitonic emissions is reduced.…”

The Science and Practice of Metal-Organic Vapor Phase Epitaxy (MOVPE)

“…Studies that have attempted to incorporate silicon into GaSb have identified it as an acceptor [241]. GaSb presents a challenge for silicon, as there is no hydride to direct incorporation because metal-organic antimony is used.…”

Analysis of Er incorporation on GaSb substrates by diffusion

“…For Er diffused crystals the two exciton peaks observed in the reference spectrum on fig.1, have disappeared, while one peak centered at 0.801eV appears. This peak can be related with the line BE3 identified in the bibliography [9,10] as a recombination of excitons with an acceptor. It is know that Er ions normaly form compounds such as ErSb in antimonide materials [2].…”