Suppression of nonradiative recombination by V-shaped pits in GaInN/GaN quantum wells produces a large increase in the light emission efficiency
Suppression of nonradiative recombination by V-shaped pits in GaInN/GaN quantum wells produces a large increase in the light emission efficiency
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DOI：
10.1103/physrevlett.95.127402
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发表时间：
2005-09-16
影响因子：
8.6
通讯作者：
Hinze, P
中科院分区：
文献类型：
--
作者：
Hangleiter, A;Hitzel, F;Hinze, P
尽管在（AlGaIn）N异质结构中普遍存在高密度的螺纹位错，但这种结构的发光效率非常高。将高效率归因于有源GaInN量子阱区域的成分波动甚至相分离已经成为一种普遍现象。由此产生的载流子的局部化被认为可以防止它们在缺陷处以非辐射方式重新组合。在这里，我们发现随机无序不是关键，而是在合适的生长条件下，装饰缺陷的六边形v形凹坑呈现出狭窄的侧壁量子阱，其有效带隙明显大于规则c面量子阱。因此，大自然提供了一种独特的、迄今为止尚未认识到的机制，产生了一种潜在的景观，通过在每个缺陷周围提供能量屏障，有效地屏蔽了缺陷本身。
Despite the high density of threading dislocations generally found in (AlGaIn)N heterostructures, the light emission efficiency of such structures is exceptionally high. It has become common to attribute the high efficiency to compositional fluctuations or even phase separation in the active GaInN quantum well region. The resulting localization of charge carriers is thought to keep them from recombining nonradiatively at the defects. Here, we show that random disorder is not the key but that under suitable growth conditions hexagonal V-shaped pits decorating the defects exhibit narrow sidewall quantum wells with an effective band gap significantly larger than that of the regular c-plane quantum wells. Thereby nature provides a unique, hitherto unrecognized mechanism generating a potential landscape which effectively screens the defects themselves by providing an energy barrier around every defect.