Green laser diodes with constant temperature growth of InGaN/GaN multiple quantum well active region

Abstract

Increasing trench defect density in green InGaN/GaN multiple quantum wells (MQWs) has been reported to be one cause for “green gap” and creates a challenge in fabricating high-performance green laser diodes (LDs). In this article, we report methods to suppress the density of trench defects. Suppressed defect density in InGaN/GaN MQWs results in greatly improved optical quality, as indicated by increasing photoluminescence (PL) intensity and nonradiative recombination lifetime, and decreasing PL full-width-half-maximums (FWHMs), which can be as narrow as 113 meV. This enabled constant temperature growth of the InGaN/GaN MQW active region of the green LD structure and greatly improved slope efficiency.

Efficient InGaN‐Based Red Light‐Emitting Diodes by Modulating Trench Defects

“…The defects can be filled and saturated, leading to more emissions from the defective regions outside trench loops. [ 26 ] At low injections, only the red MQWs inside trenches can emit light efficiently as shown in Figure 6a. The carrier lifetime becomes longer and the diffusion length increases at low injections.…”

“…[1][2][3][4] While blue and green micro-LEDs Trench defects commonly occur inside InGaN/GaN MQWs grown by various methods. [20][21][22][23][24][25][26][27][28][29][30] The formation of trench defects is mainly related to the high In components and low growth temperatures of MQWs. [23,31,32] Previous studies show that trench defect originates from basal plane stacking fault (BSF) in MQWs.…”

“…[31][32][33] The highdensity trench defects are proven to significantly reduce internal quantum efficiency (IQE) in blue and green MQWs. [25,26,34,35] The reduction in efficiency is attributed to the increased density of nonradiative recombination centers in MQWs, likely associated with SMBs. [34] Accordingly, trench defects are considered as defective structures leading to the degradation of LED efficiency.…”

Thermally stable radiative recombination centers within trench structures of red multi-quantum wells

“…These effects contribute to a deeper insight into the mechanism behind the enhanced luminescence of QWs inside deep trenches. Besides, density-controllable trench structures can be easily introduced into the QWs by various methods, such as lowering growth temperatures [26], increasing TMIn flux [44], and decreasing V-III ratios [45]. Accordingly, trench structures are highly promising for high-efficiency red InGaN LEDs.…”