Amorphous and Nanocrystalline Semiconductors for Optoelectronic Applications: Photoconductors, Detectors and Sensors Based on a-Se Alloys and Optoelectronic Glasses

用于光电应用的非晶和纳米晶半导体：基于a-Se合金和光电玻璃的光电导体、探测器和传感器

• 批准号: RGPIN-2016-04982
• 负责人: Kasap, Safa
• 金额: $ 3.93万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709548
• 关键词: Amorphous; Nanocrystalline; Semiconductors; Optoelectronic; Applications

The DG program on optoelectronic materials for radiation detection and imaging includes a major study on doped amorphous Se-As alloys (a-Se:As) and a complimentary study on rare-earth doped glasses and glass ceramics (containing nanocrystals). a-Se alloys have one clear distinct advantage over crystalline semiconductors that they can be conveniently fabricated over large areas, which has led to their extensive commercial use in flat panel x-ray image detectors. The long term objective is to build on strength by extending our scientific and technological knowledge on doped a-Se alloy based semiconductors and devices by discoveries at the material and device levels; and advancing knowledge at the fundamental level. The design of next generation a-Se detectors, in particular for use in general radiology, CT and tomosynthesis, also needs extensive knowledge of the electrical properties of the photoconductor used in the three layers, e.g. drift mobilities, carrier trapping and recombination lifetimes, sensitivity, dark current, excess noise, thermal generation rate, x-ray induced effects (such as defect creation or damage) and relaxation effects - these alloys are glasses that age and exhibit relaxation effects. Given the availability of the Canadian Light Source (CLS), we intend to continue to use of the synchrotron facility in our research and continue to collaborate with the CLS staff; and also continue with our industrial partner in relating results to practical detectors. The research program will encompass all aspects of photoconductor research from present to new a-Se alloys (doped) in a concerted effort to relate detector performance to fundamental semiconductor properties through physical models. It will also include Sm3+ doped glasses and glass ceramics for Microbeam Radiation Therapy in which we need to accurately measure the dose profile in the microbeam at the CLS BMIT line (peak dose 2 - 3 kGy with a width 20 um). There will be a number of projects within this DG program. Typical examples: (a) Study of optoelectronic properties of new doped a-Se alloys as a function of temperature and electric field toward enhanced p-i-n structures (thicker i-layer) with lower dark currents and higher applied fields. (b) Study of the x-ray energy dependence of photoconductivity of a-Se alloys, MTF, DQE as a function of operating field, temperature, total dose and dose rate. (d) Study of the effects of x-ray irradiation on the photoconductor properties and hence on the sensitivity and DQE of the actual detector. (e) Discovering new Sm-doped optoelectronic glasses (OEGs) that are tissue equivalent for better MRT dose distribution monitoring and addressing current problems (energy dependence). The impact of the work is the generation of new knowledge on doped a-Se alloys with new compositions for the design and development of next generation flat panel x-ray detectors and new OEGs for high-dose dosimetry.

用于辐射检测和成像的光电材料的DG计划包括一项有关掺杂的无定形SE-AS合金（A-SE：AS）的主要研究，以及一项关于稀有地球掺杂玻璃和玻璃陶瓷（含有纳米晶体）的免费研究。与晶体半导体相比，A-SE合金可以在大面积上方便地制造出一个明显的优势，这导致了它们在平板X射线图像探测器中的广泛商业用途。长期目标是通过在材料和设备水平的发现上扩展我们对基于A-SE合金的半导体和设备的科学和技术知识来建立力量；并在基本层面提高知识。下一代A-SE探测器的设计，特别是用于一般放射学，CT和Tomosynsiss中，还需要对三层中使用的光电导体的电性能进行广泛的了解，例如漂移迁移率，载流子捕获和重组寿命，灵敏度，暗电流，多余的噪声，热产生速率，X射线诱导的效果（例如产生缺陷或损害）和放松效应 - 这些合金是年龄和显示弛豫效果的眼镜。鉴于加拿大光源（CLS）的可用性，我们打算在我们的研究中继续使用同步器设施，并继续与CLS员工合作；并继续与我们的工业合作伙伴一起将结果与实用探测器联系起来。该研究计划将涵盖从现在到新的A-SE合金（掺杂）的光电导体研究的各个方面，以通过物理模型将探测器性能与基本半导体属性联系起来。它还将包括用于微束放射疗法的SM3+掺杂玻璃和玻璃陶瓷，我们需要在CLS BMIT线处准确测量Microbeam中的剂量剖面（峰剂量2-3 kgy，宽度为20 UM）。此DG程序中将有许多项目。典型示例：（a）研究新掺杂的A-SE合金的光电特性是温度和电场的函数，朝着增强的P-I-N结构（较厚的I层），具有较低的深色电流和较高的施加场。 （b）研究A-SE合金，MTF，DQE光电导率的X射线能量依赖性是工作场，温度，总剂量和剂量率的函数。 （d）研究X射线辐照对光电导体特性的影响，因此研究对实际检测器的灵敏度和DQE的影响。 （e）发现新的SM掺杂光电玻璃（OEG），它们是组织等效物，以更好地监测MRT剂量分布和解决当前问题（能量依赖性）。这项工作的影响是对掺杂的A-SE合金的新知识产生，并具有新的成分，用于设计和开发下一代平板X射线探测器，以及用于高剂量剂量测定法的新OEG。