Optical polarization properties of (11-22) semi-polar InGaN LEDs with a wide spectral range
Optical polarization properties of (11-22) semi-polar InGaN LEDs with a wide spectral range
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宽光谱范围 (11-22) 半极性 InGaN LED 的光学偏振特性
DOI：
10.1038/s41598-020-64196-w
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发表时间：
2020
影响因子：
4.6
通讯作者：
Poyiatzis N
中科院分区：
文献类型：
--
作者：
Poyiatzis N
对生长在高晶体质量半极性（11-22）模板上的一系列半极性InGaN发光二极管（LED）进行了电致发光偏振测量。这些LED的发射波长覆盖从443到555 nm的宽光谱区域。为了研究铟含量和注入电流对偏振特性的影响，已经进行了系统的研究，其中已经观察到在大约470 nm处的清晰的偏振切换。最短波长的LED（443 nm）显示出正的0.15偏振度，而最长波长的LED（555 nm）显示出负的-0.33偏振度。所有发射波长大于470 nm的较长波长LED都表现出负偏振度，并且它们进一步表明偏振度对注入电流的依赖性随着发射波长的增加而增强。此外，极化度的绝对值随注入电流的增加而减小。相比之下，443 nm蓝色LED的偏振度随着注入电流的变化而保持恒定。这种差异可以归因于价电子带的态密度（DOS）的显着差异。
Electroluminescence polarization measurements have been performed on a series of semi-polar InGaN light emitting diodes (LEDs) grown on semi-polar (11–22) templates with a high crystal quality. The emission wavelengths of these LEDs cover a wide spectral region from 443 to 555 nm. A systematic study has been carried out in order to investigate the influence of both indium content and injection current on polarization properties, where a clear polarization switching at approximately 470 nm has been observed. The shortest wavelength LED (443 nm) exhibits a positive 0.15 polarization degree, while the longest wavelength LED (555 nm) shows a negative −0.33 polarization degree. All the longer wavelength LEDs with an emission wavelength above 470 nm exhibit negative polarization degrees, and they further demonstrate that the dependence of polarization degree on injection current enhances with increasing emission wavelength. Moreover, the absolute value of the polarization degree decreases with increasing injection current. In contrast, the polarization degree of the 443 nm blue LED remains constant with changing injection current. This discrepancy can be attributed to a significant difference in the density of states (DOS) of the valence subbands.