报告题目（Title）： 光电薄膜材料BaSi2的制备及其在光伏、光探测器上的应用
报 告 人（Speaker）： 杜伟杰 (上海师范大学)
报告时间（Time）： 2019年6月28日 （周五）14:00
报告地点（Place）：校本部G309
邀请人（inviter）：林贤，金钻明
报告摘要（Abstract）：
Semiconducting barium disilicide (BaSi2), which is composed of earth-abundant elements, with lots of attractive features for thin-film solar cell applications. Both a large absorption coefficient comparable to copper indium gallium diselenide and a minority-carrier diffusion length much larger than the grain size of BaSi2 can be used to improve solar cell properties. We explore the potential of semiconducting BaSi2 thin film for photovoltaic and photodetector applications. We start by describing its crystal and energy band structure, followed by discussing thin-film growth techniques and the optical and electrical properties of BaSi2 films. We use a first-principles calculation based on density-functional theory to calculate the position of the Fermi level to predict the carrier type of impurity-doped BaSi2 films using either a group III or IV element, and compare the calculated results with the experimental ones. Special attention was paid to the minority-carrier properties, such as minority-carrier lifetime, minority-carrier diffusion length, and surface passivation. The potential variations across the grain boundaries measured by Kelvin-probe force microscopy allowed us to detect a larger minority-carrier diffusion length in BaSi2 on Si(111) and Si(100). Finally, we demonstrate the operation of BaSi2-based devices and discuss prospects for future development.
