Amorphous semiconductors for optoelectronic applications: photoconductors, detectors and sensors based on se-alloys

非晶半导体，例如氢化非晶硅（a-Si：H）及其合金、非晶硒（a-Se）及其合金（a-Se：As）等，相对于晶体半导体具有一个明显的明显优点，即它们可以方便地在大面积上制造，这导致它们在光致发光器件、平板显示器（TFT显示器）、平板X射线图像检测器和柔性电子器件中的广泛商业用途。在电子和光电子器件领域，非晶半导体是一个特别重要的利基市场，加拿大在这一领域具有非常强大的竞争力。我们的长期目标和目的是通过材料层面的创新、器件层面的创新和基础层面的知识进步，扩大我们在基于a-Se合金的半导体和光电器件方面的科学和技术知识。下一代a-Se x射线图像检测器的设计还需要对三层中使用的光电导体的电学性质的广泛了解，例如每层中的电荷载流子范围、漂移迁移率x载流子寿命、过量噪声和热生成速率。到目前为止，还没有人研究过a-Se p-i-n探测器中的电子噪声的性质，我们打算把它作为一个主要的研究。我们的目标和研究将包括：（i）发现和理解a-Se：As合金的电学和光电性质作为温度和电场的函数，以增强具有较低暗电流和较高施加场的p-i-n结构;增加场将改善DQE。(ii)发现低频（1/f）噪声的行为，以实现更好的检测器设计。(iii)通过来自（i）的增强的材料性质，i层和p层的组成更稳定。(iv)开发雪崩a-Se结构与乘法，证明其适用于超灵敏光学成像和间接辐射检测。当然，这项工作的影响是对a-Se探测器的新知识的产生，具有新成分的新结构，用于下一代a-Se x射线探测器的设计和开发，以及所有固态超灵敏光学图像传感器。

Amorphous semiconductors, such as hydrogenated amorphous silicon (a-Si:H) and its alloys, amorphous selenium (a-Se) and its alloys (a-Se:As) etc, have one clear distinct advantage over crystalline semiconductors that they can be conveniently fabricated over large areas, which has lead to their extensive commercial use in photovoltaics, flat panel displays (TFT displays), flat panel x-ray image detectors, and flexible electronics. Within the field of electronic and optoelectronic devices, amorphous semiconductors represent a particularly important niche in which Canada has a very strong and competitive presence. Our long term goals and objectives are to build on strength by expanding our scientific and technological knowledge on a-Se alloy based semiconductors and optoelectronic devices by innovation at the material level, innovation at the device level and advancing knowledge at the fundamental level. The design of next generation a-Se x-ray image detectors also needs extensive knowledge on the electrical properties of the photoconductor used in the three layers, e.g. charge carrier ranges, drift mobility x carrier lifetime, excess noise and thermal generation rate in each layer. To date, no one has examined the nature of electronic noise in a-Se p-i-n detectors and we intend to take this on as a major study. Our objectives and studies will include: (i) Discovering and understanding the electrical and optoelectronic properties of a-Se:As alloys as a function of temperature and electric field toward enhanced p-i-n structures with lower dark currents and higher applied fields; increasing the field will improve the DQE. (ii) Discovering the behavior of low-frequency (1/f) noise for better detector design. (iii) More stable compositions for the i-layer and p-layer through enhanced material properties from (i). (iv) Developing avalanche a-Se structures with multiplication, demonstrating their suitability for use in ultrasensitive optical imaging and in indirect radiation detection. The impact of the work is, of course, the generation of new knowledge on a-Se detectors, novel structures with new compositions, for the design and development of next generation a-Se x-ray detectors, and all solid state ultrasenstive optical image sensors.