2017/07/13 by Sang June Cho, Dong Liu, Cho, Sang June +27
Engineering · Physics and Astronomy · #Advanced Sensor and Energy Harvesting Materials #Applied Physics (physics.app-ph) #FOS: Physical sciences #GaN-based semiconductor devices and materials #Semiconductor materials and devices
paper · pdf · doi:10.48550/arxiv.1707.04223
openalex publication_date 2017/07/13 · openalex created_date 2017/07/21 · openalex updated_date 2026/07/28
As UV LEDs are explored at shorter wavelengths (< 280 nm) into the UVC spectral range, the crystalline quality of epitaxial AlGaN films with high Al compositions and inefficient hole injection from p-type AlGaN severely limit the LED performance and development. In this work, we report on 237 nm light emission with a record light output power of 265 uW from AlN/Al0.72Ga028N multiple quantum well UVC LEDs using bulk AlN substrates and p-type silicon nanomembrane contact layers for significantly improved AlGaN film quality and hole injection, respectively. No intensity degradation or efficiency droop was observed up to a current density of 245 A/cm2, which is attributed to the low dislocation density within AlGaN films, the large concentration of holes from p-Si, and efficient hole-transport to the active region. Additionally, the emission peak at 237 nm is dominant across the electroluminescence spectrum with no significant parasitic emissions observed. This study demonstrates the feasibility of using p-Si as a hole injector for UVC LEDs, which can be extended to even shorter wavelengths where hole injection from chemically doped AlGaN layers is not feasible.