NSF-BSF: High-mobility amorphous-iodide-based channel materials for p-type thin-film transistors and complementary TFT circuitry

非技术描述：在过去的十年中，笔记本电脑等电子设备中的显示器已经发生了革命性的变化，部分原因是使用了透明导电非晶氧化物，因为它们具有加工通用性和更高的载流子迁移率，并结合了低温、大面积沉积条件。来自布朗大学和以色列理工学院的一组研究人员正在研究一类新的材料，非晶金属碘化物，如CuSnI和CuPbI，这将增加用于显示器和其他透明电路技术的透明导电材料的武器库。与其他非晶材料相比，非晶金属碘化物具有不同的物理机制：在外加电压下，电流由带正电的空穴携带。这提供了新的低功耗电路的可能性，只要这些金属碘化物的材料特性，包括杂质含量，相位和温度行为可以使用成分和加工参数进行调整。该研究项目涵盖了许多主题，从材料沉积和表征的基础实验材料科学到相变和杂质掺入的理论建模，再到原型晶体管器件制造，将布朗大学的透明电子材料和器件专业知识与以色列理工学院的尖端材料表征和建模结合在一起。该研究项目对课堂内外的教育都有影响，包括研究生支持、布朗-以色列理工学院研究生的互动和交流访问，以及向普罗维登斯地区贫困的中学生提供服务。技术描述：两位在非晶电子材料和器件物理方面具有互补专业知识的布朗实验员，与以色列理工学院在原子/纳米/微观表征和物理建模方面经验丰富的团队合作，专注于薄膜晶体管（TFTs）的高迁移率宽带隙低温p型材料的需求。pi已经确定了无定形碘化物基材料是最有前途的：它们具有宽的带隙（3 eV），高空穴迁移率（高达40 cm2/V）。S)，天然空位掺杂，并且与任意底物相容。它们也与低温沉积的无定形n型氧化锌基材料兼容，为互补TFT电路开辟了道路。Brown pi正在利用他们最近展示的高性能铟锌氧化物材料，重新配置用于原位碘化物沉积的氧化物溅射工具。布朗团队正在开发和优化a-Cu1-xMxI薄膜（M = Sn, Pb， In等）的合成，通过browwer分析研究掺杂机制，研究相稳定性，并制作TFT演示电路原型。实验工作由以色列理工学院的团队进行详细的材料表征和物理建模，他们在纳米级非晶和晶体薄膜方面拥有丰富的经验。最终的实验目标是在任意衬底上以相同的溅射沉积工艺在低温下沉积n型和p型透明导电材料。该项目为参与的研究生和本科生提供跨领域电子材料和器件领域的培训机会，为布朗-以色列理工学院的访客和学生交流，以及当地贫困中学生提供培训机会。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical description: Over the past decade, displays in electronic devices like laptops have been revolutionized in part by using transparent conducting amorphous oxides due to their processing versatility and higher carrier mobility combined with low-temperature, large-area deposition conditions. A team of investigators from Brown University and Technion (Israel) is investigating a new class of materials, amorphous metal iodides like CuSnI and CuPbI, that would add to the arsenal of transparent conducting materials for use in displays and other transparent circuit technologies. Compared to other amorphous materials, the amorphous metal iodides feature a different physical mechanism: under an applied voltage, the currents are carried by positively charged holes. This offers new low-power dissipation circuit possibilities, as long as the materials properties of these metal iodides, including impurity content, phase, and temperature behavior can be tuned using composition and processing parameters. The research program covers a number of topics, ranging from fundamental experimental materials science of material deposition and characterization to theoretical modeling of phase transformation and impurity incorporation to prototype transistor device fabrication, brings together transparent electronic material and device expertise at Brown University with cutting-edge materials characterization and modeling at the Technion. The research project has an educational impact in and out of the classroom, including graduate student support, Brown-Technion graduate student interaction and exchange visits, as well as outreach to underprivileged middle-school students in the Providence area.Technical description: Two Brown experimentalists with complementary expertise in amorphous electronic materials and device physics, in collaboration with a Technion team experienced in atomic/nano/micro characterization and physical modeling, are focusing on the need for a high-mobility wide-bandgap low-temperature p-type material for thin film transistors (TFTs). The PIs have identified amorphous iodide-based materials as the most promising: they have a wide bandgap (3 eV), high hole mobility (up to 40 cm2/V.s), native vacancy doping, and are compatible with arbitrary substrates. They are also compatible with low-temperature-deposited amorphous n-type zinc oxide-based materials, opening the way for complementary TFT circuitry. The Brown PIs are leveraging their recent demonstration of high-performance indium-zinc-oxide materials by reconfiguring an oxide sputtering tool for in-situ iodide deposition. The Brown team is developing and optimizing the synthesis of a-Cu1-xMxI thin films (M = Sn, Pb, In, and others), studying the doping mechanism via Brouwer analysis, investigating phase stability, and fabricating prototype TFT demonstrator circuits. The experimental work is complemented by the detailed materials characterization and physical modeling performed by the Technion team, that has extensive experience in nanoscale amorphous and crystalline films. The final experimental goal is to develop the deposition of both n- and p-type transparent conducting materials in the same sputter-deposition process at low temperature on arbitrary substrates. The project provides training opportunities to the participating graduate and undergraduate students in cross-cutting electronic materials and devices fields, to the Brown-Technion visitor and student exchanges, as well as to the local underprivileged middle-school students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.