title: Optical properties of nanopillar AlGaN/GaN MQWs for ultraviolet light-emitting diodes.
abstract: Nanopillar AlGaN/GaN multiple quantum wells ultraviolet light-emitting diodes (LEDs) were fabricated by nanosphere lithography and dry-etching. The optical properties of the nanopillar LEDs were characterized by both temperature-dependent and time-resolved photoluminescence measurements. Compared to an as-grown sample, the nanopillar sample has a PL emission peak blue-shift of 7 meV, a 42% enhanced internal quantum efficiency at room temperature and a reduced radiative recombination lifetime from 870 picosecond to 621 picosecond at 7K. These results are directly from the suppressed quantum confined stark effect that is due to the strain relaxation in the nanopillar MQWs, further revealed by micro-Raman measurement. Additionally, finite-difference time domain simulation also proves better light extraction efficiency in the nanopillar LEDs.
authors.forename: Peng
authors.initials: P
authors.lastname: Dong
authors.forename: Jianchang
authors.initials: J
authors.lastname: Yan
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Junxi
authors.initials: J
authors.lastname: Wang
authors.forename: Chong
authors.initials: C
authors.lastname: Geng
authors.forename: Haiyang
authors.initials: H
authors.lastname: Zheng
authors.forename: Xuecheng
authors.initials: X
authors.lastname: Wei
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Yan
authors.forename: Jinmin
authors.initials: J
authors.lastname: Li