Effect of N₂-H₂ remote plasma nitridation temperature on surface properties of Te-doped GaSb crystals

GaSb is regarded as one of the most promising near-infrared optoelectronic materials in recent years. However, due to the ease of natural oxidation of GaSb, the surface will promptly form a thick oxide layer which is highly resistant to removal, resulting in detrimental interface defects and higher surface state density. Although studies have demonstrated the feasibility of plasma for removing oxide, the ultra-high vacuum is necessary for complete removal, which poses challenges for commercial applications. Herein, we optimized the nitrogen plasma passivation process for Te-doped GaSb, combining remote plasma source with Atomic Layer Deposition (ALD) in-situ annealing to modify GaSb (001) surface, which approaches non-damaging treatment. The temperature during passivation will affect nitrogenation on GaSb surface, result in enrichment of metallic Sb when reaching 573 K, and impact emission efficiency. By setting the passivation temperature at 523 K and combining with in-situ annealing, the photoluminescence (PL) efficiency of GaSb has doubled. This demonstrates the validity of low-temperature nitrogen passivation in improving surface state and reducing defect density on GaSb.