To overcome these issues, a “dual-stage MQW” structure was

proposed to enhance the electron injection and improve the crystalline

quality of the overlying MQW.

As an effort to do so, a triangular quantum well (TQW) structure

in the InGaN/GaN MQW active region has been recently proposed

to weaken the polarization field.

In this paper, we propose a LED structure, named shallow TQW

structure, to improve the emission property of LED devices.

Experiments

FIG. 1. (a) Schematic diagram of the epitaxial LEDs with the shallow QWs structure.

Buffer layer ： low temperature , grown at 530 ℃

Si-doped n-GaN layer ： 3 μm , grown at 1050 ℃

Active region ： three pairs InGaN/GaN MQW (2.7 nm/7.5 nm, grown at 745 /865 ) with ℃ ℃ In% ＝ 16% in each InGaN well

p-GaN layer ： 200 nm , grown at 920℃

Sample A ： TQW structure

Sample B ： RQW structure

Sample C ： without shallow QWs

Shallow QWs structure ：

(b) Schematic band profiles of the shallow QWs structure and the active region of LEDs with shallow TQW (Sample A), (c) LEDs with shallow RQW (Sample B), and (d) conventional LEDs (Sample C). Diagram is not to scale.