无电学接触型氮化镓基Micro-LED器件光电性能

Photoelectric Characteristics of Non-electric Contact GaN-based Micro-LED Device

针对传统Micro-LED芯片巨量转移与键合、发光芯片与驱动电极高质量接触等技术难题,本文采用金属有机化合物化学气相沉积和原子层沉积工艺制备无电学接触型氮化镓基Micro-LED器件,研究了器件的伏安特性、亮度-频率特性、发光延迟特性及阻抗-频率特性等光电特性,并分析了器件工作机理。实验结果表明,交流驱动的无电学接触型Micro-LED器件的电流随着频率的增大而增大,且I-V特性呈线性关系。在20V_(pp)的驱动信号下,器件亮度随频率的增大先上升后下降,在频率为25 MHz时,器件亮度达到最大,且发光峰值滞后于电流峰值,说明器件的发光存在延迟。器件的等效阻抗随着频率的增大呈现先减小后趋于稳定的趋势,且器件在频率53 MHz附近出现负电容现象。

In this paper,non-electrical contact(NEC)GaN-based Micro-LED devices were prepared by metal organic chemical vapor deposition(MOCVD)and atomic layer deposition(ALD)because a series of problems would emerge,including mass transfer,bonding,and high-quality contact between chips and driving electrodes as the LED chip size is further decreased.We investigated the photoelectric characteristics of NEC Micro-LED devices,such as the current-voltage(I-V),luminance-frequency(L-F),luminescence delay and impedance-frequency(I-F)characteristics,and the working mechanism of the device is also analyzed.These experimental results indicate that the current of the NEC Micro-LED device increases with the increase of the frequency and I-V curves have linear relationships under the role of the alternating-current drive.At the driving signal of 20V_(pp),the luminances of the NEC Micro-LED device first increase and then fall with the gradual increases of the frequencies.When the frequency is 25 MHz,the luminance of NEC Micro-LED device reaches to be the maximum.Moreover,the luminescence peak lags behind the current peak,indicating that the luminescence of the device is delayed.Besides,the equivalent impedance of the NEC Micro-LED device decreases and finally tends to be stable with the increases of the frequencies and the device shows the negative capacitance phenomenon around the frequency of 53 MHz.