Electronic Properties of Amorphous Semiconductors

非晶半导体的电子特性

• 批准号: 9624002
• 负责人: J. David Cohen
• 金额: $ 10万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-15 至 1998-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9624002&HistoricalAwards=false
• 关键词: Electronic; Properties; Amorphous; Semiconductors

w:\awards\awards96\*.doc 9624002 Cohen This project involves research into the fundamental properties of defects in amorphous semiconductors. First, studies will be carried out to further verify and understand the novel type of deep defect relaxation in hydrogenated amorphous silicon (a-Si:H) that has been suggested by capacitance transient measurements in the previous phase of this research. These experimental studies will focus on (1) observing relaxation through its effect on the optical spectra associated with deep defects in a-Si:H, and (2) comparing modulated photocurrent spectra (which also indicate a defect relaxation effect) with electron spin resonance data to identify the deep defect sub-bands responsible. Second, the project will investigate the deep defect properties of a novel form of carbon containing a predominance of tetrahedral bonding (ta-C). This material has recently been made with sufficiently good semiconducting properties to be amenable to our junction capacitance methods. The disclosed deep defect properties are likely to be fundamentally different than those of the tetrahedral amorphous semiconductors based on Si and Ge. %%% Amorphous or "glassy" materials represent a true frontier area to test our understanding of solid state physics. One increasingly important class of such materials are amorphous semiconductors such as hydrogenated amorphous silicon (a-Si:H). This latter material is finding important technological applications in photovoltaics and in thin film transistor arrays used to drive liquid crystal displays (flat panel TV). However, the theoretical understanding of a-Si:H is still in its infancy. This experimental research is directed at understanding the basic electronic properties of defects in such materials. These defects currently limit their future technological exploitation. Of partic ular interest are newly discovered aspects of the defect behavior in a-Si:H which suggests a glassy aspect to the electronic structure itself. In addition, preliminary studies of the electronic properties of a relatively new type of amorphous semiconductor, tetrahedral amorphous carbon (the amorphous counterpart of crystalline diamond) will be initiated. ***

w：\awards\awards96\*.doc 9624002 Cohen 该项目涉及对非晶半导体中缺陷的基本性质的研究。首先，将进行研究，以进一步验证和理解氢化非晶硅（a-Si：H）中的深缺陷弛豫的新类型，这已被建议在本研究的前一阶段的电容瞬态测量。这些实验研究将集中在（1）通过其对a-Si：H中与深缺陷相关的光谱的影响来观察弛豫，以及（2）将调制光电流谱（其也指示缺陷弛豫效应）与电子自旋共振数据进行比较，以识别负责的深缺陷子带。 其次，该项目将研究一种新型碳的深缺陷特性，这种碳主要是四面体键合（ta-C）。 这种材料最近已经制成具有足够好的半导体特性，可以适用于我们的结电容方法。 所公开的深缺陷性质可能是 与那些 的 Si和Ge基四面体非晶半导体。 无定形或“玻璃状”材料代表了一个真正的前沿领域，以测试我们对固态物理的理解。一类越来越重要的此类材料是非晶半导体，例如氢化非晶硅（a-Si：H）。 后一种材料在光电子学和用于驱动液晶显示器（平板电视）的薄膜晶体管阵列中找到了重要的技术应用。然而，理论上的理解 的 a-Si：H仍在其 婴儿期。 本实验研究旨在了解此类材料中缺陷的基本电子特性。这些缺陷目前限制了其未来的技术开发。 特别感兴趣的是新发现的a-Si：H中的缺陷行为的方面，这表明电子结构本身的玻璃态方面。此外，还对一种较新型的非晶半导体的电子性质进行了初步研究， 四面体无定形碳（ 晶体金刚石的非晶对应物）将被引发。 ***