Optimization Of Surface Passivation For Suppressing Leakage Current In Gasb Pin Devices

The suppression of leakage current via surface passivation plays a critical role for GaSb-based optoelectronic devices. In this Letter the authors carefully optimise the sulfur passivation parameters for improving the performance of GaSb p-i-n devices. Two competing processes are evaluated during the sulfur passivation process: the hydrolysis of HS- ions that aide surface passivation and the re-oxidation, respectively. Upon the optimisation of sulfur passivation parameters and subsequent encapsulation with atomic layer deposition Al2O3, the surface resistivity significantly increased from 4.3 k Omega .cm to 28.6 k Omega .cm, leading to a 19.1 times drop in dark current at room temperature for the GaSb p-i-n structure. This Letter provides a repeatable and stable passivation approach for improving the optoelectronic performance of GaSb-based devices.