Recombination rates in green-yellow InGaN-based multiple quantum wells with AlGaN interlayers
Recombination rates in green-yellow InGaN-based multiple quantum wells with AlGaN interlayers
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DOI：
10.1063/1.5126965
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发表时间：
2019-12-07
影响因子：
3.2
通讯作者：
Wierer, Jonathan J., Jr.
中科院分区：
文献类型：
--
作者：
Al Muyeed, Syed Ahmed;Sun, Wei;Wierer, Jonathan J., Jr.
显示了发出黄绿光并在 AlGaN 中间层 (IL) 中使用不同 Al 成分生长的 InGaN/AlGaN/GaN 多量子阱 (MQW) 中的复合率。通过转换辐射效率、吸收和微分载流子寿命的测量结果，可以确定辐射率和非辐射率。 IL Al 成分控制着 MQW 的晶格弛豫（由 X 射线倒易空间映射确定），从而控制缺陷的形成。对于大多数赝晶 MQW，Shockley-Read-Hall (SRH) A 系数最小化，并且与较短（蓝色和绿色）波长的报告类似。它比传统的 InGaN/GaN MQW 小一个数量级，并且是使用 IL 提高辐射效率的最重要因素。由于电子-空穴波函数重叠的减少，辐射 B 系数也降低了，并且对于大多数赝晶 MQW 来说达到最小值。然而，A 的降低更为显着，并导致辐射效率的整体提高。这些复合率测量证实，如果 SRH 复合受到控制，那么随着发射波长的增加而严重减少辐射复合是实现在低至中等电流密度下工作的高效率、长波长 InGaN MQW 发射器的主要挑战之一。由 AIP Publishing 许可发布。
The recombination rates in InGaN/AlGaN/GaN multiple quantum wells (MQWs) emitting in the green-yellow and grown with different Al compositions in the AlGaN interlayer (IL) are shown. By transforming measurements on radiative efficiency, absorption, and differential carrier lifetime, the radiative and nonradiative rates are determined. The IL Al composition controls lattice relaxation of the MQWs, as determined by X-ray reciprocal space mapping, and, therefore, defect formation. For the most pseudomorphic MQWs, the Shockley-Read-Hall (SRH) A coefficient is minimized and is similar to reports at shorter (blue and green) wavelengths. It is an order of magnitude smaller than a conventional InGaN/GaN MQW and is the most significant factor behind the improvement in radiative efficiency using the IL. The radiative B coefficient is also reduced and a minimum for the most pseudomorphic MQWs due to a reduction in the electron-hole wave-function overlap. However, the decrease in A is more significant and leads to an overall improvement in the radiative efficiency. These recombination rate measurements confirm that if the SRH recombination is controlled, then the severe reduction of radiative recombination with an increased emitting wavelength is one of the main challenges in realizing high efficiency, long-wavelength InGaN-based MQW emitters operating at low to moderate current densities. Published under license by AIP Publishing.