Yang J, Zhao D G, Jiang D S, Li X, Liang F, Chen P, Zhu J J, Liu Z S, Liu S T, Zhang L Q, Li M
Opt Express. 2017 May 1;25(9):9595-9602. doi: 10.1364/OE.25.009595.
Series of green laser diodes (LDs) with different (In)GaN barrier layers are investigated. It is found that the optical confinement factor of multi-quantum well (MQW) always increases with increasing indium content of InGaN barrier layer, which results in a decrease of threshold current when indium content of InGaN barrier layer increases from 0 to 5%. However, when a high In content InGaN barrier is used (> 5%), both threshold current and slop efficiency of LDs deteriorate. It may be attributed to the waste of carriers in the potential well at the interface between the last barrier (LB) and the upper waveguide (UWG) layers, which is induced by the piezoelectric polarization effect in high In content InGaN LB layer. Therefore, a new LD structure using a thin thickness of the LB layer to reduce the effect of polarization shows a low threshold current and a high output power even when the In content of barrier layers is as large as 7%.
研究了具有不同（In）GaN势垒层的一系列绿色激光二极管（LD）。发现多量子阱（MQW）的光限制因子总是随着InGaN势垒层铟含量的增加而增加，这导致当InGaN势垒层的铟含量从0增加到5%时阈值电流降低。然而，当使用高In含量的InGaN势垒（>5%）时，LD的阈值电流和斜率效率都会恶化。这可能归因于在最后一个势垒（LB）和上波导（UWG）层之间的界面处势阱中载流子的浪费，这是由高In含量的InGaN LB层中的压电极化效应引起的。因此，一种使用薄厚度LB层来降低极化效应的新型LD结构即使在势垒层的In含量高达7%时也显示出低阈值电流和高输出功率。
