| 摘要: | 研究期間：10108~10207;This research, Organic Light-Emitting Field-Effect Transistor Lasers, will deal with electrically pumped organic lasers by using organic gain structure in field-effect transistors incorporated with optical resonance cavities. This project must be achieving high-quality field-effect transistors and best resonance cavities. The overall research includes characterization of luminescent organic semiconductors, investigation of electrical and optical mechanisms in field-effect transistors, design and fabrication of resonance cavities, integration of light-emitting transistors and resonance cavities, and measurement of optical and electric characteristics of laser devices. Organic light-emitting field-effect transistor comprises of an organic light-emitting layer, a dielectric layer, and source, drain, gate three-terminal electrodes. The main advantage is its lateral source/drain configuration and the capability of positioning of light-emission zone in the channel with applied bias, which allows the vertical light output to be unaffected by lateral electrodes, and thereby the out-coupling efficiency is higher than conventional organic light-emitting diodes. Moreover, organic light-emitting field-effect transistors offer high structural compatibility and flexible device parameters, which is advantageous of optimizing electrical-optical properties of organic materials, improving external quantum efficiency, reducing exciton nonradiative loss, and integrating with various resonance cavities. Thus, for research of electrically-pumped organic lasers, organic light-emitting field-effect transistor is very promising. The current bottleneck of realizing electrically pumped organic lasers is due to requirement of extremely high threshold of current density. Therefore, this project will be firstly choosing high gain, highly conductive organic luminescent materials, and then on one hand optimizing electro-optical properties of light-emitting field-effect transistors to enhance current density and external quantum efficiency, and on the other hand utilizing resonance cavity effect to improve amplified spontaneous emission and to reduce threshold current. The optical resonance cavities investigated in this project are mainly based on photonic crystals and microcavities with one pair of highly reflective mirrors. In order to enhance the intensity of resonance cavity, the optimized structure parameters, cavity modes, and phase-matching conditions are simulated. Furthermore, this project will also be investigating the dependence of optical gain on current density, exciton density, and external quantum efficiency in laser devices. By developing an integrated research based on organic material characterizations, device physics of field-effect transistors, and mechanisms of resonance cavity, electrically pumped organic laser with low threshold is expected to be achieved. |
