GOALI: High Efficiency, Large Area Solar Cell Devices Based on Crystalline Si Thin Films by Low Temperture Growth and Solid State Laser Crystallization

薄膜太阳能电池、有源矩阵显示器和带有驱动电子设备的显示器需要在廉价、大面积和/或透明的衬底(如玻璃)上沉积晶体硅薄膜，以提高性能和降低制造成本。要实现这一目标，困难在于：(1)玻璃的非晶态性质使得不可能采用现有的生长技术来利用衬底的结晶特性。(2)相对便宜的玻璃无法承受生长晶体硅薄膜所需的高温处理。为了克服这些问题，我们提出了一种固体激光晶化技术，在这种技术中，激光脉冲会导致近表面区域的熔化和再凝固，但较短的激光脉冲持续时间阻碍了对底层衬底的持续加热，使该工艺与玻璃衬底兼容。该计划的目标是了解使用近红外波长的固体激光器进行激光结晶的基础科学，通过在玻璃衬底上通过低温工艺生长非晶硅薄膜，然后使用半导体二极管激光器作为种子层进行晶化，然后通过等离子体增强化学气相沉积来结晶更厚的薄膜，以展示高效太阳能电池器件。研究工作是国家科学基金GALI计划下的学术和产业合作。大学教职员工和研究生将与BP太阳能公司的科学家和工程师团队密切合作。大学产业合作将为学生提供更多与工业科学家合作的机会，并使用他们额外的最先进的设备设施。除了太阳能电池技术的改进，该项目还将为学生提供薄膜生长、激光加工和电子器件制造方面的教育，这些都是非常需要的技能和当前感兴趣的重要领域。拟议的计划将有一个强大的外展活动，如高中教师在太阳能和激光应用领域工作的暑期体验，参观工业，以及在当地博物馆展示改进的公共知识装置，并激发人们对科学和工程的兴趣。

Thin film solar cells, active matrix displays and displays with driver electronics require crystalline silicon thin films on inexpensive, large area and/or transparent substrates such as glass for improved performance and low manufacturing costs. To achieve this goal the difficulties are: (1) amorphous nature of glass makes it impossible to employ current growth techniques that take advantage of crystalline character of the substrate. (2) the inability of relatively inexpensive glass to withstand high processing temperatures required for growth of crystalline silicon films. To overcome these problems we propose a solid state laser crystallization technique where laser pulse causes melting and re-solidification of the near surface region however short duration of laser pulse prevents sustained heating of the underlying substrate and makes the process compatible with glass substrates. The goal of the proposed program is to understand the basic science of laser crystallization using solid state lasers with near infrared wavelengths and grow amorphous silicon films by a low temperature process on glass substrates and then crystallize them by semiconductor diode lasers for seed layer followed by thicker films by plasma enhanced chemical vapor deposition to demonstrate high efficiency solar cell devices.The research effort is Academy-Industry collaboration under the National Science Foundation GOALI program. The university faculty and graduate students will work in close collaboration with the team of scientists and engineers at the BP Solar Corporation. The university industry collaboration will provide additional opportunity for students to work with industrial scientists and use of their additional state of the art equipment facilities. Besides improvements in solar cell technology, this project will provide education to students in thin film growth, laser processing and electronic device fabrication, which are highly desired skills and important areas of current interest. The proposed program will have a strong outreach activity such as summer experience for high school teachers to work in solar energy and laser applications area, visit to industry and a display in a local museum of improved device for public knowledge and generate interest in science and engineering.