Authors: S.Y. Lo, P.J. Wu, R.H Yeh and J.W. Hong
Affilation: National Central University, Taiwan
Pages: 107 - 110
Keywords: ultraviolet, detector, Ge, nanocrystal
Since the observation of photoluminescence from porous Si, nanocrystalline Si and Ge have extensively been studied because it would open a possibility for indirect-gap semiconductors for optoelectronic applications. Nayfeh et al. reported ultraviolet (UV) detectors created by deposition of Si nanoparticles active medium. Contrary to bulk Ge, reducing the size of Ge crystals enhances the quantum-mechanical spatial confinement effects, which effectively creates a “direct” wide-bandgap material and this makes it sensitive to UV light. In this paper, we presented a metal-semiconductor-metal (MSM) UV detector on Si substrate by using Ge nanocrystals embedded in SiO2 matrix as active medium. The Ge nanocrystals were formed by selective oxidation of hydrogenated amorphous SiGe/Si (a-SiGe:H/a-Si:H) multilayer prepared by a conventional plasma-enhanced chemical vapor deposition (PECVD) system and this may offer an opportunity for integration on silicon substrate.