Airbus Group Innovations , D-81663 Munich, Germany.
Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences , D-80335 Munich, Germany.
Nano Lett. 2017 Feb 8;17(2):615-621. doi: 10.1021/acs.nanolett.6b03299. Epub 2017 Jan 23.
We demonstrate that the complex adsorption behavior of HO on InGaN/GaN nanowire arrays is directly revealed by their ambient-dependent photoluminescence properties. Under low-humidity, ambient-temperature, and low-excitation-light conditions, HO adsorbates cause a quenching of the photoluminescence. In contrast, for high humidity levels, elevated temperature, and high excitation intensity, HO adsorbates act as efficient photoluminescence enhancers. We show that this behavior, which can only be detected due to the low operation temperature of the InGaN/GaN nanowires, can be explained on the basis of single HO adsorbates forming surface recombination centers and multiple HO adsorbates forming surface passivation layers. Reversible creation of such passivation layers is induced by the photoelectrochemical splitting of adsorbed water molecules and by the interaction of reactive HO and OH ions with photoactivated InGaN surfaces. Due to electronic coupling of adsorbing molecules with photoactivated surfaces, InGaN/GaN nanowires act as sensitive nanooptical probes for the analysis of photoelectrochemical surface processes.
我们证明，通过其环境依赖的光致发光特性，可以直接揭示 HO 在 InGaN/GaN 纳米线阵列上的复杂吸附行为。在低湿度、环境温度和低激发光条件下，HO 吸附物会导致光致发光猝灭。相比之下，对于高湿度水平、高温和高激发强度，HO 吸附物则作为有效的光致发光增强剂。我们表明，由于 InGaN/GaN 纳米线的低操作温度，只能检测到这种行为，它可以基于单个 HO 吸附物形成表面复合中心和多个 HO 吸附物形成表面钝化层来解释。吸附水分子的光电化学分裂以及反应性 HO 和 OH 离子与光激活 InGaN 表面的相互作用，诱导了这种钝化层的可逆形成。由于吸附分子与光激活表面的电子耦合，InGaN/GaN 纳米线作为用于分析光电化学表面过程的灵敏纳米光学探针。
