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器件的显示器需要在廉价、大面积和/或透明基板（如玻璃）上使用晶体硅薄膜，以提高性能和降低制造成本。实现这一目标的困难在于：(1)玻璃的无定形特性使其不可能采用当前的生长技术来利用基板的结晶特性。(2)相对便宜的玻璃无法承受生长晶体硅薄膜所需的高温。为了克服这些问题，我们提出了一种固态激光结晶技术，其中激光脉冲引起近表面区域的熔化和再凝固，但激光脉冲持续时间短，可以防止底层基板的持续加热，并使该工艺与玻璃基板兼容。本计划的目标是了解激光结晶的基础科学，使用近红外波长的固态激光器，在玻璃衬底上通过低温工艺生长非晶硅薄膜，然后用半导体二极管激光器进行种子层结晶，然后用等离子体增强化学气相沉积法将其变厚，以展示高效率的太阳能电池器件。这项研究工作是在国家科学基金会GOALI项目下的学术界和工业界合作进行的。该大学的教师和研究生将与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的机会与工业科学家一起工作，并使用他们额外的最先进的设备设施。除了改进太阳能电池技术外，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，这些都是目前非常需要的技能和重要的领域。该计划将有一个强有力的推广活动，如高中教师在太阳能和激光应用领域的暑期体验，参观工业和在当地博物馆展示改进的设备，以提高公众的知识和科学和工程兴趣。

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.