Fabrication and photoelectric properties of epi-GaN nanowires on sapphire

• Main Authors: Shiao-Wen Wang, 王曉雯
• Other Authors: Chia-Chun Chen
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/43330158990123154228

碩士 === 國立臺灣師範大學 === 化學研究所 === 93 === One-dimensional (1D) nanostructures, such as NWs, NTs, have attracted much attention due to their novel and interesting properties in physics and chemistry. One-dimensional semiconducting structures have been served as the next generation materials to achieve the goal of nano-scaled electronic and optoelectronic devices. However, the difficulties in dealing with the electrical contacts on these nanosized materials have been limiting the potential applications of 1D nanostructures. In this work, we present the fabrication of a new ultra-violet (UV) detector with metal-semiconductor-metal (M-S-M) structure using epitaxially grown GaN nanowires (NWs) as the photoconducting materials. The GaN layer on the M-S-M structure was patterned in patches with 10 mm gaps by standard photolithography and reactive ion etching process. The catalyst-grown GaN NWs have average diameters of 50±5 nm and lengths of 10±2 mm and link the two side walls of the GaN block electrodes. Photoconductivity (PC) spectra show that the GaN NWs exhibit a single absorption at 3.4 eV which is attributed to the inter-band transition. The maximal responsivity of the GaN NWs UV-detector is around 4X104 A/W which is higher than the reported values for GaN films by two orders of magnitude. The origin of this high responsivity of the GaN NWs could be attributed to low lattice scattering and high carrier mobility in this low-dimensional material.