Jeon K S, Sung J H, Lee M W, Song H Y, Shin H Y, Park W H, Jang Y I, Kang M G, Choi Y H, Lee J S, Ko D H, Ryu H Y
J Nanosci Nanotechnol. 2016 Feb;16(2):1798-801. doi: 10.1166/jnn.2016.11939.
We investigate the strain difference in InGaN/GaN multiple quantum wells of blue light-emitting diode (LED) structures grown on silicon(1 11) and c-plane sapphire substrates by comparing the strength of piezo-electric fields in MQWs. The piezo-electric fields for two LED samples grown on silicon and sapphire substrates are measured by using the reverse-bias electro-reflectance (ER) spectroscopy. The flat-band voltage is obtained by measuring the applied reverse bias voltage that induces a phase inversion in the ER spectra, which is used to calculate the strength of piezo-electric fields. The piezo-electric field is determined to be 1.36 MV/cm for the LED on silicon substrate and 1.83 MV/cm for the LED on sapphire substrate. The ER measurement results indicate that the strain-induced piezo-electric field is greatly reduced in the LED grown on silicon substrates consistent with previous strain measurement results by micro-Raman spectroscopy and high-resolution transmission electron microscopy.
我们通过比较多量子阱（MQWs）中压电场的强度，研究了在硅（1 11）和c面蓝宝石衬底上生长的蓝光发光二极管（LED）结构的InGaN/GaN多量子阱中的应变差异。通过使用反向偏置电反射光谱（ER）测量在硅和蓝宝石衬底上生长的两个LED样品的压电场。通过测量在ER光谱中引起相位反转的施加反向偏置电压来获得平带电压，该电压用于计算压电场的强度。确定硅衬底上的LED的压电场为1.36 MV/cm，蓝宝石衬底上的LED的压电场为1.83 MV/cm。ER测量结果表明，与先前通过显微拉曼光谱和高分辨率透射电子显微镜进行的应变测量结果一致，在硅衬底上生长的LED中，应变诱导的压电场大大降低。
