Localized Electronic States in Amorphous Semiconductors

[7049 . 46]泰勒这是一个研究无序半导体电子和结构特性的新项目。本研究将回答在低硫浓度下IV族硫族玻璃和在高金属浓度下金属硫族玻璃的结构、缺陷和掺杂机制等问题。该研究的第二个重要组成部分将回答有关硫系玻璃中光学诱导顺磁性和光变暗的微观起源的问题，特别是在上面提到的两个模型系统中。科学方法涉及广泛的程序，利用几种生长技术，磁共振光谱，光谱学，各种光学和磁共振技术的组合，以及电测量。具体目标是(1)了解局部秩序的细节，(2)研究内在缺陷及其相关亚稳态，作为平均配位数的函数，以及(4)识别有助于光变暗的缺陷。这是对非晶半导体继续研究的更新建议。非晶半导体为许多电子应用提供了晶体半导体的廉价替代品。一个重要的例子是将非晶硅用于开关（薄膜晶体管），用于个人电脑平板显示器和平板电视屏幕。这些材料的使用受到当前制造的各种电子或光学设备随时间变化的阻碍。在这项研究中获得的信息将大大增加我们对作为电流载体的电子行为的理解。这些信息将证实或反驳已开发的适用于所有非晶半导体的特定模型。例如，半导体之所以能成为有用的电开关，其最重要的特性是能够通过一种被称为掺杂的过程显著改变电导率。这项研究将使人们对非晶半导体中的掺杂机制有更全面的了解，从而最终用于制造更可靠的器件。＊＊＊

9704946 Taylor This is a renewal project for the study of the electronic and structural properties of disordered semiconductors. This research will answer questions concerning the structure, defects and doping mechanisms in Group IV chalcogenide glasses at low chalcogen concentrations and in metal chalcogenide glasses at high metal concentrations. A second important component of the research will answer questions concerning the microscopic origins of optically- induced paramagnetism and of photodarkening in chalcogenide glasses, especially those in the two model systems mentioned above. The scientific approach involves a broadly based program that utilizes several growth techniques, magnetic resonance spectroscopy, optical spectroscopies, various combinations of optical and magnetic resonance techniques, and electrical measurements. The specific objectives are (1) to understand details of the local order, (2) to study the intrinsic defects, and their associated metastabilities, as a function of average coordination number, and (4) to identify the defects that contribute to photodarkening. %%% This is a renewal proposal for a continuing study of amorphous semiconductors. Amorphous semiconductors provide inexpensive alternatives to crystalline semiconductors for many electronic applications. One important example is the use of amorphous silicon for the switches (thin-film transistors) in flat-panel displays for personal computers and flat television screens. The use of these materials is hindered by changes that occur with time in the various electronic or optical devices that are currently manufactured. The information gained in this research will greatly increase our understanding of the behavior of electrons which are the carriers of electrical current. This information will confirm or refute specific models that have been developed to apply generally to all amorphous semiconductors. For example, the most important property of semiconductors that mak es them useful as switches of electricity is the ability to change the electrical conductivity dramatically via a process known as doping. This research will result in a more general understanding of doping mechanisms in amorphous semiconductors - an understanding that can eventually be used to manufacture more reliable devices. ***