| Summary: | 碩士 === 國立臺灣海洋大學 === 光電科學研究所 === 97 === In this study, we compare the photo-electrochemical (PEC) properties of n- and p-GaN modified with gold nano-particle in 1M HCl solution for water splitting. The Au nano-particle was deposited on GaN by ion beam sputtering system, with the average diameter being about 10nm. The PEC properties were conducted in 1M HCl solution with Ag/AgCl electrode as reference electrode, Pt as counter electrode. As for the light source, we used a xenon lamp with filters to simulate the sun light. The light power density was fixed at 100mW/cm2. The PEC I-V curve results showed quite different behaviors between n- and p-GaN. After gold particle deposited, further changes occurred. For p-GaN, Au nano-particle deposition enhanced the photocurrent, whereas n-GaN shows a suppressed result. Although the saturation current is similar to the original p-GaN, the IPCE (Incident Photo to Current Conversion Efficiency) results of the Au particle deposited p-GaN demonstrated an enhanced efficiency and a largely increased photocurrent (-0.016��-0.418 mA/cm2) under zero bias (vs. the Pt electrode). The highest IPCE under zero bias is about 24% at 300nm. From the shifted on-set potential, the enhanced mechanism was explained by the change in surface band-bending after Au deposition. It is believed that the Au ano-paticle modified p-GaN should show its potential in acting as a good photocathode in water splitting.
|
|---|
