Preparation and photoluminescence of self-standing nanoporous InGaN/GaN MQWs via UV-assisted electrochemical etching

The self-standing InGaN-based multiple quantum wells (MQWs) thin films with the vertically aligned nanoporous InGaN/GaN layer, were electrochemically etched in nitric acid (HNO3) solution under ultraviolet (UV) light, and then transferred to stainless steel cloth and quartz substrates, respectively. Compared to the as-grown sample, the etched and transferred thin films show an enhanced and blue-shift photoluminescence (PL) emission. The PL enhancement is attributed to the improved internal quantum efficiency (IQE) which is ascribed to the improved crystalline quality of MQWs, and the increased light extraction efficiency (LEE) which is ascribed to the high light-extracting surface area and light-guiding effect of the vertically aligned nanoporous InGaN/GaN structure. And the blue-shift can be attributed to stress relaxation of MQWs and variable In content in InGaN layer.

Automated summary

The InGaN-based multiple quantum wells thin films were etched and transferred, showing enhanced and blue-shift photoluminescence emission compared to the original sample. The enhancement is attributed to improved crystalline quality and increased light extraction efficiency due to the structure of vertically aligned nanoporous InGaN/GaN. The blue-shift is caused by stress relaxation of MQWs and variable In content in InGaN layer.