Developing a deeper understanding of doping and defects in metal oxide semiconductors

金属氧化物（MO）半导体在许多技术平台中发挥着至关重要的作用，从大面积电子/显示到生物传感和光催化等各种应用。总的来说，MOs提供了一套具有可调谐电子特性的材料，包括电荷载流子迁移率和密度，高光学透明度，并提供了大量稳定的纳米结构。此外，通过取代掺杂可以进一步调整MOs的电学和光学性质。在这里，我们建议研究几种n型MOs，包括In2O3 SnO2， ZnO和WO3以及它们的掺杂类似物，通过既定的化学和物理沉积工艺，包括原子层沉积（ALD），化学气相沉积（CVD）和新兴的基于溶液的工艺，在温度< 450℃下制备。我们预计缺陷的化学性质和相应的电学和光学性质会有很大的不同。利用这个合作研究项目中可用的表征工具，我们的目标是解决一些相关的研究问题，即：-如何通过取代掺杂实现稳定和可控的自由电子浓度？-我们能否增强和/或抑制缺陷的双重作用，即减少缺陷引起的载流子重组，但提高n型电导率？我们是否可以提高我们对内在和外在掺杂剂对改变载流子迁移率的相互作用的理解？-主要缺陷类型及其浓度和能量如何随加工条件而变化？

Metal oxides (MO) semiconductors play a vital role in number of technology platforms ranging from large area electronics/displays through to applications as diverse as biosensing and photocatalysis. Collectively MOs provide a suite of materials with tuneable electronic properties, including charge carrier mobility and density, high optical transparency and offer access to a plethora of stable nanostructures. Furthermore, the electrical and optical properties of MOs can be further tuned by substitutional doping.Here we propose to investigate several n-type MOs, including In2O3 SnO2, ZnO and WO3 as well as their doped analogues Fabricated by established chemical and physical deposition processes, including atomic layer deposition (ALD), chemical vapour deposition (CVD) and by emerging solution based processes all at temperatures < 450 C. Whilst the different synthetic approaches should result in compositionally similar films, we anticipate significant variation in defect chemistry and correspondingly differences in electrical and optical properties. Using the characterisation tools available in this collaborative research project we aim to address a number of interrelated research questions, namely:- How can stable and controllable free electron concentrations be achieved through substitutional doping?- Can we enhance and/or supress the dual role of defects i.e. reduce defect induced charge carrier recombination but enhance n-type conductivity?- Can we improve our understanding of the interplay between intrinsic and extrinsic dopants on change carrier mobility?- How the major defect types, their concentration and energies vary with processing conditions?