Proof of Solid State Cathodoluminescence by Using Brightness Waveform
LIU Ming1, 2,CHEN Xiao-hong3,XU Zheng1,TENG Feng1,YI Li-xin1,GAO De-wen2,GUO Li-qun2
1. Institute of Optoelectronics Technology, Beijing Jiaotong University, Beijing 100044, China 2. Beijing Institute of Petro-Chemical Technology, Beijing 102617, China 3. Institute of Semiconductors, CAS, Beijing 100083, China 4. Tianjin University Postdoctoral Working Station, Economy and Technological Development Area Postdoctoral Working Station, Tianjin Zhong-Huan San-Jin Ltd, Tianjin 300457, China
Abstract：Three different inorganic-organic hetero-junctions (A: ITO/SiO2/Alq3/Al, B: ITO/Alq3/SiO2/Al and C: ITO/SiO2/Alq3/SiO2/Al ) were fabricated. The emission can be observed only under positive bias in devices A and B, but under both biases in device C according to their brightness waveforms. With increasing voltage, the increase in blue emission in devices B and C is faster than that in green emission. This is because that the recombination of hot electrons and holes, i.e., electron-hole pairs, produced blue emission in devices B and C, and the recombination of electrons injected from Al with the accumulated holes, which are excited by hot electrons, produced green emission in device A. Hence, the emissions of the devices are attributed to not only the recombination of electrons and accumulated holes, but also the cathodoluminescence-like (CL-like) emission.
