Investigation of photoelectrochemical-oxidized p-GaSb films

Abstract

GaSb oxide films were directly formed on the p-GaSb films using the bias-assisted photoelectrochemical (PEC) oxidation method. X-ray photoelectron spectroscopy analysis indicated that the resulting GaSb oxide films consisted of Ga2O3, Sb2O3, and Sb2O5. Different from the non-PEC oxides, the PEC derived oxide contained much more Sb2O5 than Sb2O3. Besides, the interface state density between the PEC oxide and p-GaSb was lower than that of the ordinary oxide/p-GaSb interface. The high quality of the PEC-oxidized GaSb films was attributed to the increase of the stable Sb2O5 content and decrease of the elemental Sb content in the films.

Performance improvement mechanisms of bias-assisted photoelectrochemical treated GaSb-based solar cells with ITO nanorod array

“…Table listed the short circuit current density ( J sc ), open circuit voltage ( V oc ), fill factor ( FF ), and conversion efficient ( η ) of these solar cells A, B, and C. It was found that the short circuit current density of 57.09 mA/cm 2 for solar cell B was larger than that of 50.82 mA/cm 2 for solar cell C. More surface recombination centers were induced on the as‐etched surface of solar cell C, because the etching process for removing the p + ‐GaSb layer caused damage to the p ‐GaSb surface. To reduce the induced surface recombination centers, the bias‐assisted PEC oxidation process was performed to form a PEC oxide layer on the p ‐GaSb surface as an oxide passivation layer after the etching process in solar cell B. Consequently, the interface state density between the PEC oxide passivation layer and the p ‐GaSb was reduced to decrease the carrier recombination on the surface of solar cell B. Therefore, the improvement in short circuit current density was attributed to that the surface carrier recombination in solar cell B was suppressed by the bias‐assisted PEC passivation function.…”

“…During the PEC growth process, the laser beam intensity and the bias voltage were kept to be 6.5 mW/cm 2 and 4 V, respectively, and the pH value of the electrolytic solution was set around 12.5. The working mechanism of the bias‐assisted PEC oxidation method was reported, previously . To reduce the light reflection from the surface of the solar cells, an ITO nanorod array was grown on the p ‐GaSb surface using an oblique‐angle electron‐beam deposition system with an optimized oblique‐angle of 30°.…”

“…Among them, gallium antimonide (GaSb)‐based semiconductors are promising materials of solar cells, because they can effectively absorb the sun light in the long wavelength range because of its narrow energy bandgap. However, the GaSb surface can be easily oxidized in an air ambience to form a native oxide layer, including Ga 2 O 3 , Sb 2 O 3 , and Sb 2 O 5 . Generally, the by‐product Sb 2 O 3 easily reacts with GaSb to form Ga 2 O 3 and the elemental Sb .…”

“…In this work, the bias‐assisted photoelectrochemical (PEC) oxidation method was used to directly grow a thin PEC oxide layer on the p ‐GaSb surface as the passivation layer for the GaSb‐based solar cells. During the PEC oxide process, Sb 2 O 5 was easily formed from the reaction of Sb 2 O 3 , OH − , and holes . Consequently, the formation of elemental Sb resided at the interface between the native oxide layer and the GaSb layer was avoided because of the effective reduction of the reaction of Sb 2 O 3 with GaSb.…”

Single-GaSb-nanowire-based room temperature photodetectors with broad spectral response

“…As one of the important III/V compound semiconductor material, gallium antimonide (GaSb) has attracted considerable attention as potential building blocks for a variety of optical and electronic components, such as infrared imaging device, thermoelectric sensor, and high-speed electronics, especially photodetectors [11][12][13][14]. Although GaSbbased photodetectors usually exhibited photoconduction features, till now, most of the GaSb-based photodetectors are built on either bulk materials, thin films or nanostructured superlattice.…”