Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung 202, Taiwan.
Nanotechnology. 2013 Feb 8;24(5):055401. doi: 10.1088/0957-4484/24/5/055401. Epub 2013 Jan 16.
Enhanced photoelectrochemical (PEC) performances of Ga(2)O(3) and GaN nanowires (NWs) grown in situ from GaN were demonstrated. The PEC conversion efficiencies of Ga(2)O(3) and GaN NWs have been shown to be 0.906% and 1.09% respectively, in contrast to their 0.581% GaN thin film counterpart under similar experimental conditions. A low crystallinity buffer layer between the grown NWs and the substrate was found to be detrimental to the PEC performance, but the layer can be avoided at suitable growth conditions. A band bending at the surface of the GaN NWs generates an electric field that drives the photogenerated electrons and holes away from each other, preventing recombination, and was found to be responsible for the enhanced PEC performance. The enhanced PEC efficiency of the Ga(2)O(3) NWs is aided by the optical absorption through a defect band centered 3.3 eV above the valence band of Ga(2)O(3). These findings are believed to have opened up possibilities for enabling visible absorption, either by tailoring ion doping into wide bandgap Ga(2)O(3) NWs, or by incorporation of indium to form InGaN NWs.
研究表明，通过在 GaN 上原位生长 Ga2O3 和 GaN 纳米线（NWs），可增强其光电化学（PEC）性能。在相似的实验条件下，Ga2O3 和 GaN NWs 的 PEC 转换效率分别达到 0.906%和 1.09%，而 GaN 薄膜的转换效率仅为 0.581%。研究发现，在 NWs 和衬底之间生长的低结晶度缓冲层对 PEC 性能有害，但在适当的生长条件下可以避免该层。GaN NWs 表面的能带弯曲会产生一个电场，将光生电子和空穴彼此分离，从而防止复合，这被认为是增强 PEC 性能的原因。Ga2O3 NWs 的增强的 PEC 效率得益于通过位于 Ga2O3 价带上方 3.3 eV 的缺陷带的光学吸收。这些发现为通过在宽带隙 Ga2O3 NWs 中进行离子掺杂，或者通过掺入铟形成 InGaN NWs 来实现可见光吸收提供了可能性。
