First-principles calculations of electronic and optical properties of disordered and amorphous CuI-based ternary alloys

我们建议对透明半导体铜-卤化物三元化合物和合金的电子能带结构、输运系数和光谱进行预测计算，并进一步发展最好的固体理论和计算方法。在研究单元FOR2857的第一阶段，我们的目标是优化p型CuI的导电性和透明度。在深入研究了闪锌矿γ-CuI相之后，我们研究了其他晶相、不同的化学计量比、缺陷和代位掺杂。通过对包括铜、碘和元素周期表中另一种元素直至铋的三元体系相图的计算，预测和表征了新的稳定化合物。我们的主要目标是提出在不影响透明度的情况下提高空穴迁移率和集中度的方法。在第二个资助期，我们希望在现有成果的基础上再接再厉。首先，我们将扩大搜索空间，将焦点从CuI转移到CuI基三元晶体。我们的计划包括：(I)我们预选的p型透明半导体CuI基三元化合物的高通量掺杂工程；(Ii)深入分析铜空位和I配位的修饰对CuI基晶体电子性质的影响；(Iii)非晶态三元薄膜的计算表征。其次，我们将推进三元相图的热力学分析，以考虑到无序对CuI基合金热力学稳定性和电子性质的影响。像往常一样，我们将过滤出不满足与目标应用程序相关的要求的系统。最好的候选系统将被传递到标准密度泛函理论(DFT)之外的精确电子表征上，应用我们从多体微扰理论推导出的DFT和含时间DFT的新近似。在我们计算调查的所有阶段，不断向FOR2857的合作伙伴传输相关信息将有助于加快工作并最大限度地发挥其影响。在整个项目期间收集的大量数据将使用机器学习进行分析，以提取p型透明导体的设计规则。

We propose to perform predictive calculations of electronic band structures, transport coefficients and optical spectra of transparent semiconducting copper-halide ternary compounds and alloys, using and further developing the best available theoretical and computational approaches for solids. In the first period of the research unit FOR2857 we targeted the optimization of conductivity and transparency of p-type CuI. After a thorough study of the zincblende phase γ-CuI, we investigated other crystalline phases, different stoichiometries, defects and substitutional doping. We predicted and characterized novel stable compounds from the calculation of phase diagrams of ternary systems including Cu, I and another element of the periodic table up to Bi. Our main objective was and remains to propose ways to enhance hole mobility and concentration without compromising transparency. In the second funding period we want to build upon present results. First, we will enlarge the search space, moving the focus from CuI to CuI-based ternary crystals. Our plan includes: (i) high-throughput engineering of dopants for CuI-based ternaries that we have pre-selected as promising p-type transparent semiconductors; (ii) deep analysis of the effect of Cu vacancies and modifications of I coordination on the electronic properties of CuI-based crystals; (iii) computational characterization of amorphous ternary films. Second, we will push forward the thermodynamic analysis of the ternary phase diagrams to include entropic terms, and therefore account for effects of disorder on thermodynamic stability and electronic properties of CuI-based alloys. As usual, we will filter out systems that do not satisfy requirements related to the targeted application. The best candidate systems will instead be passed forward for accurate electronic characterization beyond standard density-functional theory (DFT), applying new approximations for DFT and time-dependent DFT, that we have derived from many-body perturbation theory. At all stages of our computational investigation, a continuous transfer of relevant information to the partners of FOR2857 will allow to accelerate the work and maximize its impact. The large amount of data collected during the whole duration of the project will be analyzed using machine learning to extract design rules for p-type transparent conductors.