GaN基蓝光micro-LED的电致发光光谱、结温和载流子温度研究

Investigation of the Electroluminescence, Junction Temperature, and Carrier Temperature of GaN-Based Blue Micro-LED

摘要:

结温及载流子温度作为影响LED发光效率的重要参数而广受关注。本论文研究了GaN基蓝光集成传感micro-LED的光致发光(EL)光谱、载流子温度等随结温的变化规律。通过内置集成传感单元的芯片设计实现了GaN基蓝光micro-LED在0.04-53.4 A/cm2^{电流密度下}结温和EL光谱的实时精确测量,并将正向电压法测量结温的低温端范围拓展至123 K。结果表明,低温下由于载流子泄漏、串联电阻的原因,结温与正向电压的线性斜率发生变化。对EL光谱使用高能侧斜率法计算得到不同电流密度下的载流子温度。发现载流子温度与结温在所研究的结温和电流密度范围内可以近似用二次方程拟合,并对载流子温度随结温和电流密度变化的规律进行了分析和解释。上述针对GaN基蓝光集成传感micro-LED的光电热特性的研究有利于未来提升器件性能。

Abstract:

Junction temperature and carrier temperature are widely concerned as significant parameters affecting LED luminous efficiency. This paper investigated the electroluminescence (EL) spectrum, junction temperature, and carrier temperature of GaN-based blue micro-LED. The accurate real-time measurement of junction temperature and EL spectrum of GaN-based blue micro-LED at current densities of 0.04-53.4 A/cm2 were conducted by using the chip design with a built-in integrated sensor unit, and the range of the low-temperature end of the junction temperature measurement was extended to 123 K using the forward voltage method. The results showed that the linear slope of junction temperature and forward voltage changed due to carrier leakage and series resistance at low temperature. The high-energy slope of EL spectra was used to calculate the carrier temperature at different current densities. It was found that the carrier temperature and junction temperature can be approximately fitted by a quadratic equation within the range of junction temperature and current density under study and the law of the variation of the carrier temperature with junction temperature and current density was analyzed and explained. The above-mentioned research on the optical, electrical, and thermal characteristics of GaN-based blue micro-LED with an integrated sensor unit is conducive to improving the device’s performance in the future.