Study on Porous Silicon and Its Application on Light-Emitting Diode

• Main Authors: Yuong-Chih Tsai, 蔡永智
• Other Authors: Shui-Jinn Wang
• Format: Others
• Language: en_US
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/47285601133087868492

碩士 === 國立成功大學 === 電機工程研究所 === 83 === Due to the indirect energy gap and its energy gap is only .11 ev at room temperature, silicon shows a very poor opticaladiative efficiency and only produces light ouside the visibleange. However, by utilizing quantum confinement effect, roomemperature visible PL can be observed from porous Si(PS) repared by electrochemical etching. The quantum confinementffect is found resulting in widening the bandgap andransferring the indirect bandgap into the direct bandgap. In this thesis, the morphology of PS is investigatednd the PS prepared under different anodization conditionsxhibit different morphologies are presented. By properlydjusting the anodization parameters, such as the anodic time,urrent density, the concentrations of HF solution, and lightllumination during anodization, etc., the porosity in PS cane well-controlled.It is found that the PL peak position showsblueshift with increasing the porosity, which can be explainedy the quantum confinement effect.Furthermore, the Raman spectrumeveals that there are microstructures in the PS and shows aownshift of the Raman peak accompanied by brodening theinewidth with reducing the sizes of the microstructures. Theseesults confirm that the quantum confinement effect do play ann important role in the origin of the luminescence from PS. In the device applications, the light-emitting diode basedn porous Si (PS-LED) has been successfully fabricated. Finally,he selected-area PS and PS-LED have also been fabricateduccessfully with conventional photolithography.Further work isrgently needed to find possibility for implementing Si-basedEIC with conventional photolithographic technique in the nearuture.