Conductance Fluctuations in Amorphous Silicon

小行星9424277 本研究项目的主要目的是阐明和研究 电导涨落的物理机制 氢化非晶硅（a-Si：H）。 本实验室以前对a-Si：H中1/f噪声和随机电报开关噪声的研究表明，噪声来源于电阻随时间变化的非均匀电流丝，可能是由于键合氢的运动引起键合重排，从而改变了缺陷结构 的材料。 非晶硅膜 将 在明尼苏达大学的RF等离子体增强化学气相沉积系统中合成，其中掺杂水平和沉积条件系统地变化。 这些薄膜的随机电报噪声的温度和偏压的依赖性将被调查，以确定是否开关噪声来自电流微通道。 随着a-Si：H薄膜的性质的改变，表征1/f噪声的非高斯统计将被研究。 最后，在迁移率边缘的长程无序将通过比较热电势和电导率激活能之间的差异来表征，并且将与噪声行为以及光学和结构性质相关。 这些电影。 这些努力将显着提高我们的理解波动现象的a-Si，一个技术上重要的材料。 氢化非晶硅（a-Si：H）越来越多地用于光伏器件、输入扫描仪、传真机、复印机和平板显示器的薄膜晶体管。 所有这些都需要非晶半导体的大表面积优势。 随着这些电子器件被制造得更小，非晶硅中的基本电噪声最终限制了器件性能。 因此，如果非晶半导体要实现其技术潜力，对噪声现象的微观机制的理解至关重要。 本研究项目的主要目的是阐明和研究这些机制，因为薄膜半导体的性质是系统变化的。 我们实验室以前对氢化非晶硅中的电子噪声的研究发现，噪声本身表现出随时间变化的涨落，即噪声中有噪声！ 噪声的噪声的研究提供了重要的信息，有关的程度，电子无序和长程相关的材料。 这项研究将显着推进我们的知识波动现象，特别是在非晶硅，以及提高我们的理解的物理非线性弛豫过程中的无序固体，一般。 ***

9424277 Kakalios The principal aim of this research project is to elucidate and study the physical mechanisms underlying conductance fluctuations in hydrogenated amorphous silicon (a-Si:H). Previous studies of 1/f noise and random telegraph switching noise in a-Si:H in our laboratory suggest that the noise arises from inhomogeneous current filaments whose resistance varies in time, possibly due to the motion of bonded hydrogen inducing bonding rearrangements which alter the defect structure of the material. Amorphous silicon films will be synthesized in an rf plasma-enhanced chemical vapor deposition system at the University of Minnesota, for which the doping level and deposition conditions are systematically varied. The temperature and bias dependence of the random telegraph noise of these films will be investigated to determine if the switching noise arises from current microchannels. The non-Gaussian statistics which characterize 1/f noise will be investigated as the properties of the a-Si:H films are varied. Finally, the long-range disorder at the mobility edge will be characterized by comparing the difference between the thermopower and conductivity activation energies, and will be correlated with the noise behavior as well as with the optical and structural properties of these films. These efforts will significantly improve our understanding of the fluctuation phenomena in a-Si, a technologically important material. %%% Hydrogenated amorphous silicon (a-Si:H) is increasingly used in photovoltaic devices, input scanners, fax machines, photocopiers, and thin-film transistors for flat-panel displays. All of these require the large surface area advantages of amorphous semiconductors. As these electronic devices are made smaller, fundamental electrical noise in the amorphous silicon ultimately limits device performance. An understanding of the microscopic m echanisms responsible for the noise phenomena is therefore crucial if amorphous semiconductors are to achive their technological potential. The principal aim of this research project is to elucidate and study these mechanisms as the properties of the thin-film semiconductor are systematically varied. Previous studies of the electronic noise in hydrogenated amorphous silicon in our laboratory discovered that the noise itself exhibits time-dependent fluctuations, that is, the noise has noise! Studies of the noise of the noise provide important information concerning the degree of electronic disorder and long-range correlations in the material. This research will significantly advance our knowledge of fluctuation phenomena in amorphous silicon in particular, as well as improve our understanding of the physics of non-linear relaxation processes in disordered solids, in general. ***