Preparation of Crystalline Selenium Thin Films as the Photoconductor of Visible Light Image Sensors

• Main Author: 林健翔
• Other Authors: 潘扶民
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/95986329184755673432

碩士 === 國立交通大學 === 材料科學與工程學系所 === 104 === This research developed crystalline selenium(c-Se) as a new photosensitive layer at visible wavelength and used it in the future 8K ultra-high definition image sensor. Because c-Se had a higher absorption coefficient than Si, which was used in traditional photosensitive layer, it could enhance the image sensor sensitivity. A higher absorption coefficient of photosensitive layer would keep higher sensitivity when reduced the pixel size. By this material we could develop a high sensitivity and high definition image sensor. To fabricate c-Se photodetector, the ZnO hole blocking layer and Te adhesion layer were prepared by reactive sputter deposition on ITO substrate. The a-Se was deposited by thermal evaporation. The a-Se could be transformed into c-Se by annealing under atmosphere. In order to understand c-Se photodetector sensing ability between different wavelength of light, we used a 465 nm blue light and a 620 nm red light as light sources and compared c-Se with a-Se photosensitive layer. We also researched the effects of c-Se crystal size on dark and photo current by electrical measurement. According to our research, the thickness of 500 nm c-Se had a higher photocurrent compared with 500 nm a-Se owing to its high absorption coefficient. The photocurrent of c-Se photodetector increased gradually with crystal size and related to combination phenomenon in grain boundary. There was no significant different in dark current of c-Se photodetector between different c-Se crystal size.