Ge Quantum-Dots Formed by Selective Oxidation of a-Si:H/a-SiGe:H Multilayer and Fabrication of Ge Quantum-Dots MSM Photodetectors

• Main Authors: Pei-Jen Wu, 吳培甄
• Other Authors: Jyh-Wong Hong
• Format: Others
• Language: en_US
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/qkk6s2

碩士 === 國立中央大學 === 電機工程研究所 === 94 === Ge-rich quantum-dots embedded in an oxide matrix have been fabricated by oxidizing the as-deposited hydrogenated amorphous Si0.91Ge0.09 layer or hydrogenated amorphous Si/Si0.91Ge0.09 multilayer. The formation of Ge-rich quantum-dots was realized by the Ge atoms’ segregation and agglomeration during thermal oxidation. The cthodoluminescence (CL) spectra for the obtained samples, measured at room-temperature, were within the violet-band and peaked approximately at 3.1 eV (391 nm), which was independent of the average size of Ge quantum-dots, and a higher CL intensity was observed when the average size of Ge quantum-dots decreased. The metal-semiconductor-metal photodetectors based on Ge quantum-dots have also been fabricated. The effects of finger spacing and metal-electrode materials on characteristics of MSM-PDs with interdigitated electrodes have been studied. The device photo-current increased, dark-current decreased and response speed increased as finger spacing increased. The Cr-electrode could suppress the device dark-current more effectively, as compared with the Ti-electrode.