Unity quantum efficiency in III-nitride quantum wells at low temperature: Experimental verification by time-resolved photoluminescence
Unity quantum efficiency in III-nitride quantum wells at low temperature: Experimental verification by time-resolved photoluminescence
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DOI：
10.1063/5.0055368
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发表时间：
2021-07-05
影响因子：
4
通讯作者：
Hangleiter, Andreas
中科院分区：
文献类型：
--
作者：
Henning, Philipp;Sidikejiang, Shawutijiang;Hangleiter, Andreas
利用时间分辨光致发光（PL）测量，我们提出了一个实验验证的III-N量子威尔斯在低温下的100%的内量子效率（IQE）。传统的IQE测量，如温度和功率相关的PL，需要低温归一化，通常假设IQE为100%。这种假设忽略了即使在低温下也可能存在的剩余非辐射复合。从时间分辨的PL测量，有效的电荷载流子的衰减时间和辐射复合的寿命可以分别评估。我们指出，当有效载流子衰减仅由辐射复合主导时，量子阱的低温IQE对应于100%。在这种情况下，温度相关的测量显示了有效寿命与辐射寿命的同步上升，因为在2D系统中只有辐射寿命随温度增加。同时，非辐射过程被热激活，这导致寿命随温度降低。因此，绝对IQE测量成为可能，因为我们提供了一个强大的指标，在量子威尔斯在低温下的非辐射复合的情况下。
Using time-resolved photoluminescence (PL) measurements, we present an experimental verification for 100% internal quantum efficiency (IQE) of III-N quantum wells at low temperatures. Conventional IQE measurements, such as temperature- and power-dependent PL, require a low-temperature normalization, where usually an IQE of 100% is assumed. This assumption neglects remaining nonradiative recombination that may be present even at cryogenic temperatures. From time-resolved PL measurements, the effective charge carrier decay time and the lifetime of radiative recombination can be evaluated separately. We state that the low-temperature IQE of a quantum well corresponds to 100%, whenever the effective charge carrier decay is dominated only by a radiative recombination. In this case, the temperature-dependent measurements show a synchronous rise of the effective lifetimes together with the radiative lifetimes, since only the radiative lifetime increases with temperature in a 2D system. At the same time, nonradiative processes are thermally activated, which results in a decreasing lifetime with temperature. Thereby, absolute IQE measurements become possible, since we provide a robust indicator for the absence of nonradiative recombination in quantum wells at low temperature.