Synthesis of Single Crystal Gold-in-Ga2O3 Nanowires and Their Application in Resistive Switching Memory

• Main Authors: Hsu, Chia-Wei, 許家瑋
• Other Authors: Chueh, Yu-Lun
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/32083155107590079131

博士 === 國立清華大學 === 材料科學工程學系 === 101 === This thesis is commitment on the fabrication, growth mechanism, statistical model and resistive switching characteristic of one-dimensional gold-in-Ga2O3 heterostructure nanowires. We have successfully fabricated gold continuous nanowire or discrete nanoparticles embedded with twin boundary in the Ga2O3 shell layer using gallium (Ga) as growth source with gold (Au) as catalyst. The growth temperature was 800 ℃ with a pressure of 1 × 10-2 torr in a three-zone vacuum furnace through Vapor-Liquid-Solid (VLS) growth mechanism. Using the generalized logit regression to model the relationship between fabrication parameters and ratios of the heterostructures, we find that the heterostructure nanowire density can be increased at higher temperature and larger catalyst size resulted from non-uniform supersaturation between edge side and center area of Au-Ga droplet. Finally, we investigated the resistive switching behaviors of single gold-in-Ga2O3 core-shell nanowire, for which the bipolar resistive switching characteristics with invariable set and reset voltages can be obtained. We attribute the unique property of invariance to the built-in conduction paths of gold core. This invariance allows us to fabricate many resistive switching cells with the same operating voltage by depositing repetitive metal electrodes along a single nanowire. Other characteristics of these core-shell resistive switching nanowires include comparable driving electric field with other thin film and a remarkable on/off ratio more than 3 orders of magnitude at a low driving voltage of 2 V. A smaller but still impressive on/off ratio of 10 can be obtained at an even lower bias of 0.2 V. These characteristics of gold-in-Ga2O3 core-shell nanowires make it a viable candidate for future high-density resistive memory devices.