Zhang Huafan, Ebaid Mohamed, Tan Jeremy, Liu Guangyu, Min Jung-Wook, Ng Tien Khee, Ooi Boon S
Opt Express. 2019 Feb 18;27(4):A81-A91. doi: 10.1364/OE.27.000A81.
InGaN-based nanowires (NWs) have been investigated as efficient photoelectrochemical (PEC) water splitting devices. In this work, the InGaN/GaN NWs were grown by molecular beam epitaxy (MBE) having InGaN segments on top of GaN seeds. Three axial heterojunction structures were constructed with different doping types and levels, namely n-InGaN/n-GaN NWs, undoped (u)-InGaN/p-GaN NWs, and p-InGaN/p-GaN NWs. With the carrier concentrations estimated by Mott-Schottky measurements, a PC1D simulation further confirmed the band structures of the three heterojunctions. The u-InGaN/p-GaN and p-InGaN/p-GaN NWs exhibited optimized stability in pH 0 electrolytes for over 10 h with a photocurrent density of about -4.0 and -9.4 mA/cm, respectively. However, the hydrogen and oxygen evolution rates of the Pt-treated u-InGaN/p-GaN NWs exhibited a less favorable stoichiometric ratio. On the other hand, the Pt-decorated p-InGaN/p-GaN NWs showed the best PEC performance, generating approximately 1000 µmol/cm hydrogen and 550 µmol/cm oxygen in 10 h. The band-engineered p-InGaN/p-GaN axial NWs-heterojunction demonstrated a great potential for highly efficient and durable photocathodes.
基于氮化铟镓的纳米线（NWs）已被研究作为高效的光电化学（PEC）水分解装置。在这项工作中，通过分子束外延（MBE）在氮化镓籽晶顶部生长具有氮化铟镓段的氮化铟镓/氮化镓纳米线。构建了三种具有不同掺杂类型和水平的轴向异质结结构，即n型氮化铟镓/ n型氮化镓纳米线、未掺杂（u）的氮化铟镓/ p型氮化镓纳米线和p型氮化铟镓/ p型氮化镓纳米线。通过莫特-肖特基测量估计载流子浓度，PC1D模拟进一步证实了三种异质结的能带结构。未掺杂的氮化铟镓/ p型氮化镓和p型氮化铟镓/ p型氮化镓纳米线在pH值为0的电解质中表现出优化的稳定性，分别在超过10小时内光电流密度约为-4.0和-9.4 mA/cm²。然而，经过铂处理的未掺杂氮化铟镓/ p型氮化镓纳米线的析氢和析氧速率表现出不太理想的化学计量比。另一方面，铂修饰的p型氮化铟镓/ p型氮化镓纳米线表现出最佳的PEC性能，在10小时内产生约1000 µmol/cm²的氢气和550 µmol/cm²的氧气。能带工程化的p型氮化铟镓/ p型氮化镓轴向纳米线异质结展示了作为高效耐用光电阴极的巨大潜力。
