Surface and interface electronic properties of emerging oxide semiconductors: a feasibility study of CdO

近年来，氮化物和氧化物半导体结晶质量的提高导致人们对这些材料在未来器件应用中的兴趣与日俱增。对于大多数微电子和光电子设备来说，半导体和金属触点之间的界面在很大程度上决定了它们的性质。因此，为了充分发挥这些氮化物和氧化物半导体的潜力，有必要了解它们的近表面和界面区的基本性质。我们在国际上对传统III-V半导体和氮化物材料的近表面空间电荷性质的了解做出了贡献，包括稀有III-V氮化物，例如GaAs和InNSb[EPSRC授予GR/R93872/01和GR/S56030/01]，以及III-氮化物，例如InN和InGaN[EPSRC授予EP/C535553/1]-使用高分辨率电子能量损失谱(HREELS)和X射线光电子发射光谱(XPS)的表面敏感技术。这项建议旨在扩展我们开发的实验和理论方法，首次研究金属有机气相外延生长的高质量单晶CDO的近表面和界面性质，这是InN的II-VI类似物。我们将使用HREELS和XPS相结合的方法来研究清洁的CDO表面和不同电负性元素沉积时形成的界面的空间电荷分布。此外，这项研究将确定从较成熟的氮化物转向较不发达的氧化物的可行性。

Improvements in the crystalline quality of both nitride- and oxide-based semiconductors in recent years has resulted in increasing interest in these materials for future device applications. For the majority of micro- and opto-electronic devices, the interfaces between the semiconductors and the metal contacts largely dictates their properties. Consequently, to fully realise the potential of many of these nitride- and oxide-based semiconductors it is necessary to understand the fundamental properties of their near-surface and -interface regions. We have contributed internationally with our understanding of the near-surface space-charge properties of conventional III-V semiconductors and nitride-based materials - including dilute III-V nitrides e.g. GaNAs and InNSb [EPSRC grants GR/R93872/01 and GR/S56030/01] and III-nitrides e.g. InN and InGaN [EPSRC grant EP/C535553/1] - with the surface sensitive techniques of high resolution electron energy-loss spectroscopy (HREELS) and x-ray photoemission spectroscopy (XPS). This proposal seeks to extend the experimental and theoretical methodology we have developed to invesitgate for the first time the near-surface and -interface properties of metalorganic vapour-phase epitaxy grown high-quality single-crystalline CdO, the II-VI analogue of InN. We will employ a combination of HREELS and XPS to investigate the space-charge profiles of both clean CdO surfaces and interfaces formed when elements of different electronegativities are deposited. Furthermore, this study will determine the feasibility of moving from the more established nitrides towards the less developed oxides.