Analysis of stress-induced inhomogeneous electroluminescence in GaN-based green LEDs grown on mesh-patterned Si (111) substrates with n-type AlGaN layer

• 作者: Chang-Da Zheng Jian-Li Zhang Jiang-Dong Gao Jun-Lin Liu Quan-Jiang Lv Yi-Hong Zhang
• 来源期刊: 中国物理B（英文版）
• 年，卷（期）: 2020,（8）
• 所属期刊栏目: CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC,AND OPTICAL PROPERTIES
• 页码范围: 538-543
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/1674-1056/ab96a2

摘要

Inhomogeneous electroluminescence (EL) of InGaN green LEDs grown on mesh-patterned Si (111) substrate had been investigated.Sample with n-AlGaN inserted between the pre-strained layers and the first quantum well showed the inhomogeneous EL in the low current density range.Near-field EL emission intensity distribution images depicted that inhomogeneity in the form of premature turn-on at the periphery of the LED chip,results in stronger emission intensity at the edges.This premature turn-on effect significantly reduces the luminous efficacy and higher ideality factor value due to locally current crowding effect.Raman measurement and fluorescence microscopy results indicated that the partially relaxed in-plane stress at the edge of the window region acts as a parasitic diode with a smaller energy band gap,which is a source of edge emission.Numerical simulations showd that the tilted triangular n-AlGaN functions like a forward-biased Schottky diode,which not only impedes carrier transport,but also contributes a certain ideality factor.