Enhancing the light output power of deep ultraviolet light-emitting diodes with a ultra-thin p-type layer through etching non-ohmic contact p-GaN region

In this study, we employ the etching non-ohmic contact p-type region to enhance the performance of deep ultraviolet light-emitting diodes (DUV-LEDs) with ultra-thin (62 nm) p-type layers. Experimental results demonstrate that a shallow etching depth (12 nm) can enhance the light output power (LOP) of DUV-LEDs by 10.9%. However, when the etching depth is increased slightly to 18 nm, the LOP of DUV-LEDs decreases by 42%. Moreover, the forward leakage current of the device is severely deteriorated, while the reverse leakage current remains unaffected. This is because ultra-thin p-type layers fail to prevent the etch-inducing defects from propagating into the active region, thereby inducing a defect-related parallel diode and reducing the internal quantum efficiency. Conversely, a shallower etching depth can enhance light extraction efficiency and mitigate etch-inducing defects in the DUV-LEDs with ultra-thin p-type layers. These findings indicate that the p-type layer etching process for improving the performance of advanced DUV-LEDs with an ultra-thin p-type layer must be carefully optimized.