The enhanced optical property of chemical passivated n type GaSb
In the paper, Te-doped n type GaSb was passivated by (NH4)2S, the optical and surface properties of passivated GaSb were investigated by PL and AFM. After passivation treatment, the luminescence intensity of GaSb was enhanced. The passivation time would also affect luminescence intensity and the surface smooth of GaSb.
Luminescence from indented Te-doped GaSb crystals
Cathodoluminescence in the scanning electron microscope has been used to investigate the effect of plastic deformation, produced by indentation, in Te-doped GaSb crystals. Deformation has been found to cause a strong quenching of the luminescence emission as well as spectral changes. In particular, the decrease of the near band edge emission is accompanied by the relative increase of the defect band A and of the 730 meV band related to the VGaGaSbTeSb centres. Annealing treatments up to 600 °C lead to partial recovery of the deformation induced defects, and reveal the existence of Te out-diffusion processes from the deformed areas.
Electrical properties of GaSb Schottky diodes and p-n junctions
Abstract The electrical properties of Schottky diodes and p-n junctions on GaSb ((100), doped with 2 × 10 17 cm −3 tellurium) were examined. Capacitance-voltage measurements at 300 K show barrier heights of0.65 eV (Al), 0.6 eV (Au, In, Pd), 0.5 eV (Ga) and 0.42 eV (Sb). The barrier heights tend to track the band gap increase as the temperature is lowered. Forward I-V characteristics of the GaSb Schottky diodes at 300 K have ideality factors in the range 1.9–2.4, indicating that generation-recombination current from a near midgap center is dominating the behavior. At room temperature and below, the activation energy for J s in the expression J=J s exp (qV/nkT) is 0.24 eV. However, at higher temperatures the activation energy becomes more nearly equal to the barrier height as deduced from C-V measurements and the n value decreases below two. Deep level transient spectroscopy (DLTS) measurements reveal the presence of one electron trap with a concentration around 10 15 cm −3 at 0.25 eV below the conduction band edge. Electron beam induced current (EBIC) measurements give an electron diffusion length of 1.3 μm. In GaSb p-n + junctions grown by molecular beam epitaxy, DLTS measurements show the presence of a generation-recombination center at E v +0.33 eV with a concentration of 5×10 14 cm −3 . The effective lifetime inferred from the saturation current value is around 2×10 −9 s. For reverse bias, the mechanism of breakdown at large voltages in p-n + structures includes tunneling via local centers with an energy of around 0.3 eV. Forward and reverse characteristics can be improved by (NH 4 ) 2 S treatments for both Schottky barriers and pn + junctions.