Localized Electronic States in Amorphous Semiconductors

非晶半导体中的局域电子态

• 批准号: 9403806
• 负责人: P. Craig Taylor
• 金额: $ 33万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-07-15 至 1998-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9403806&HistoricalAwards=false
• 关键词: Localized; Electronic; States; Amorphous; Semiconductors

9403806 Taylor Technical abstract: Metal chalcogenide glasses are a model system that provides a link between the tetrahedrally-coordinated amorphous materials, such as hydrogenated amorphous silicon and the traditional chalcogenide glasses, such as selenium or arsenic selenide. The research will answer questions concerning the structure, defects and doping mechanisms in metal chalcogenides glasses where both the metal and chalcogenide atoms can be tetrahedrally coordinated. Important questions concern the microscopic origins of optically-induced paramagnetidm, of photodarkening, and potential doping mechanisms. The specific objectives are (1) to understand the details of the local structural order in metal-containing chalcogenide glasses, (2) to study the intrinsic defects in metal chalcogenide glasses as the structure is changed from low to high average coordination number, (3) to understand the p-type doping mechanism in the Cu-As-Se(S) systems, and (4) to further the understanding of the photodarkening process and the defects that contribute to photodarkening, especially those defects that involve optical anisotropies. Non-technical abstract: In order for semiconductors to be useful as electronic devices on must be able to change their electrical properties dramatically by a process called "doping". In most semiconductors where the atoms are not well ordered (amorphous semiconductors) it has generally been assumed that doping is not possible. We have demonstrated the feasibility of inefficient doping in a class of amorphous semiconductors containing sulfur. Selenium or tellurium and are investigating ways of improving the doping and expanding our understanding of the process. Amorphous semiconductors also have the property that they are metastable and that their electronic and optical characteristics can change. These metastabilities are sometimes deleterious to device performance, as in the degradation of thin-film transistors with time, but so metimes they are useful, as in the use for optically- induced index changes in inorganic photoresists. These metastabilities will be studied to understand the basic microscopic mechanism essential for the design of useful devices. ***

9403806 Taylor 技术摘要：金属硫族化物玻璃是一种模型系统，它提供了四面体配位非晶材料（例如氢化非晶硅）和传统硫族化物玻璃（例如硒或硒化砷）之间的联系。 该研究将回答有关金属硫族化物玻璃的结构、缺陷和掺杂机制的问题，其中金属和硫族化物原子都可以四面体配位。 重要的问题涉及光诱导顺磁性、光暗化的微观起源以及潜在的掺杂机制。 具体目标是（1）了解含金属硫族化物玻璃中局部结构有序的细节，（2）研究金属硫族化物玻璃结构从低平均配位数变为高平均配位数时的固有缺陷，（3）了解Cu-As-Se（S）体系中的p型掺杂机制，以及（4）进一步了解光暗化过程和缺陷 有助于光暗化，尤其是那些涉及光学各向异性的缺陷。 非技术摘要：为了使半导体能够用作电子设备，必须能够通过称为“掺杂”的过程显着改变其电性能。 在大多数原子排列不整齐的半导体（非晶半导体）中，通常认为掺杂是不可能的。 我们已经证明了在一类含硫非晶半导体中进行低效掺杂的可行性。 硒或碲正在研究改进掺杂并扩大我们对该过程的理解的方法。 非晶半导体还具有亚稳态的特性，并且其电子和光学特性可以改变。 这些亚稳定性有时对器件性能有害，例如薄膜晶体管随时间的退化，但有时它们是有用的，例如用于无机光刻胶中光致折射率变化。 将研究这些亚稳定性，以了解有用器件设计所必需的基本微观机制。 ***