The unique electronic band structure of indium nitride InN, part of the industrially significant III–N class of semiconductors, offers charge transport properties with great application potential due to its robust n-type conductivity. Here, we explore the water sensing mechanism of InN thin films. Using angle-resolved photoemission spectroscopy, core level spectroscopy, and theory, we derive the charge carrier density and electrical potential of a two-dimensional electron gas, 2DEG, at the InN surface and monitor its electronic properties upon in situ modulation of adsorbed water. An electric dipole layer formed by water molecules raises the surface potential and accumulates charge in the 2DEG, enhancing surface conductivity. Our intuitive model provides a novel route toward understanding the water sensing mechanism in InN and, more generally, for understanding sensing material systems beyond InN.

中文翻译：

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氮化铟如何感测水

氮化铟InN的独特电子能带结构是工业上重要的III–N类半导体的一部分，由于其强大的n型电导率，其电荷传输特性具有巨大的应用潜力。在这里，我们探讨InN薄膜的水感测机制。使用角度分辨光发射光谱法，核能级光谱法和理论，我们得出InN表面二维电子气2DEG的电荷载流子密度和电势，并就地监测其电子性能调节吸附的水。由水分子形成的电偶极子层提高了表面电势，并在2DEG中积累了电荷，从而提高了表面电导率。我们直观的模型为了解InN中的水感测机制提供了一条新颖的途径，并且更广泛地说，为理解InN以外的感测材料系统提供了一条新颖的途径。