本論文主要是利用一般有機發光二極體的元件架構，研究多層波導結構下有機材料的ASE現象。主要的方法是在ITO透明導電電極與有機發光層(BSB-Cz)中間插入空間層，來解決ITO電極所產生的光學損耗。實驗發現插入較BSB-Cz折射率低的有機高分子電洞傳輸層PVK並優化其厚度，可將ASE的閥值能量降到與直接鍍製BSB-Cz於玻璃基板上一樣的等級，約0.78 uJ/pulse。主要原因為PVK插入後可以改善波導模態的光場分布，減少在ITO電極的光學損耗。然而，插入高折射率的電子傳輸層TiO2則無法看到明顯的ASE現象。原因可能為TiO2折射率過高，光子容易被侷限在TiO2這層裡面，減少了光子在有機發光層裡的光放大機制。最後也模擬了一維DFB共振腔結構，找出適當的週期使共振波長吻合發光材料增益最大的波長位置，並且能運用在有電極的多層波導結構。此研究可有助於之後對電激發有機雷射的開發。 In this paper, we study ASE phenomenon of organic materials in a multilayer waveguide structure based on the general OLED device configuration. The method is to insert a spacer between the transparent electrode (ITO) and the organic emitting layer (BSB-Cz) to reduce the optical losses introduced by the ITO electrode. In the experiments, we observe that by inserting an organic polymer hole transport layer (PVK) with the refractive index lower than BSB-Cz and the thickness optimized, the ASE threshold energy can be reduced down to about 0.78 uJ/pulse, similar to as when BSB-Cz is directly deposited on the glass substrate. The main reason is that insertion of PVK can restore the waveguide mode profile and reduce the optical losses in ITO layer. However, we didn’t observe the ASE obviously when inserting the electron transport layer (TiO2) with a higher refractive index than BSB-Cz. The reason is that the high refractive index of TiO2 results in the photons essentially confined in the TiO2 layer, and hence decreasing the photon light amplification mechanism in the organic emitting layer. Finally, we simulate one dimension DFB resonator, to find out the suitable period such that the resonant wavelength can match the peak gain wavelength of organic materials. This study can be applied to multilayer waveguide structure, and the future development of electrically pumped organic lasers.
