紫外至可見光之奈米結構光偵測器

Abstract

本論文研究雙極的 MOS (metal-oxide-semiconductor) 結構增益型光偵測器的光響應情形，同時對此一元件的光電轉換機制作進一步的探討。在逆偏壓下，340-1000 nm波段的光都可觀察到有響應電流，最高光電轉換效率可達138%，其可解釋為此奈米量子點光偵測器操作在逆偏壓時，由於矽基底形成反轉層，且其上之奈米結構膜會捕獲正電荷而增強載子由反轉層注入到上電極，此效應如同電晶體中載子由射極注入到集極。最終形成奈米膜中產生之光激電流被放大之效應。

In this thesis, we constructed a two-terminal metal-oxide-semiconductor photodetector for which light is absorbed in a capping layer of silicon nanocrystals embedded in a mesoporous silica matrix on p-type silicon substrates. Operated at reverse bias, enhanced photoresponse from 340 to 1000 nm was observed. The highest optoelectronic conversion efficiency is as high as 138%. The enhancements were explained by a transistorlike mechanism, in which the inversion layer acts as the emitter and trapped positive charges in the mesoporous dielectric layer assist carrier injection from the inversion layer to the contact, such that the primary photocurrent could be amplified.