Abstract The electrical properties and deep trap spectra were compared for near-UV GaN/InGaN quantum well (QW) structures grown on free-standing GaN substrates. The structures differed by the presence or absence of a thin (110 nm) InGaN layer inserted between the high temperature GaN buffer and the QW region. Capacitance-voltage profiling with monochromatic illumination showed that in the InGaN underlayer (UL), the density of deep traps with optical threshold near 1.5 eV was much higher than in the QW and higher than for structures without InGaN. Irradiation with 5 MeV electrons strongly increased the concentration of these 1.5 eV traps in the QWs, with the increase more pronounced for samples without InGaN ULs. The observations are interpreted using the earlier proposed model explaining the impact of In-containing underlayers by segregation of native defects formed during growth of GaN near the surface and trapping of these surface defects by In atoms of the InGaN UL, thus preventing them from infiltrating the InGaN QW region. Deep level transient spectroscopy (DLTS) also revealed major differences in deep trap spectra in the QWs and underlying layers of the samples with and without InGaN ULs. Specifically, the introduction of the InGaN UL stimulates changing the dominant type of deep traps. Irradiation increases the densities of these traps, with the increase being more pronounced for samples without the InGaN UL. It is argued that light emitting diodes (LEDs) with InGaN UL should demonstrate a higher radiation tolerance than LEDs without InGaN UL.

中文翻译：

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在有和没有 InGaN 底层生长的 InGaN/GaN 单量子阱结构中的深陷阱

摘要 比较了在自支撑 GaN 衬底上生长的近紫外 GaN/InGaN 量子阱 (QW) 结构的电学特性和深陷阱光谱。这些结构的不同在于是否存在插入在高温 GaN 缓冲层和 QW 区域之间的薄 (110 nm) InGaN 层。单色照明的电容电压分析表明，在 InGaN 底层 (UL) 中，光学阈值接近 1.5 eV 的深陷阱密度远高于 QW，并且高于没有 InGaN 的结构。用 5 MeV 电子辐照大大增加了 QW 中这些 1.5 eV 陷阱的浓度，对于没有 InGaN UL 的样品，这种增加更为明显。使用较早提出的模型解释了观察结果，该模型解释了含 In 底层的影响，因为在表面附近的 GaN 生长过程中形成的天然缺陷的分离以及这些表面缺陷被 InGaN UL 的 In 原子捕获，从而防止它们渗透到InGaN QW 区。深能级瞬态光谱 (DLTS) 还揭示了具有和不具有 InGaN UL 的样品的 QW 和底层中深陷阱光谱的主要差异。具体来说，InGaN UL 的引入刺激了深陷阱的主导类型的改变。辐照会增加这些陷阱的密度，对于没有 InGaN UL 的样品，这种增加更为明显。有争议的是，具有 InGaN UL 的发光二极管 (LED) 应该比没有 InGaN UL 的 LED 表现出更高的辐射耐受性。