화학공학소재연구정보센터
Applied Surface Science, Vol.336, 89-95, 2015
Laser Induced Forward Transfer for front contact improvement in silicon heteroj unction solar cells
In this work the Laser Induced Forward Transfer (LIFT) technique is investigated to create n-doped regions on p-type c-Si substrates. The precursor source of LIFT consisted in a phosphorous-doped hydrogenated amorphous silicon layer grown by Plasma Enhanced Chemical Vapor Deposition (PECVD) onto a transparent substrate. Transfer of the doping atoms occurs when a sequence of laser pulses impinging onto the doped layer propels the material toward the substrate. The laser irradiation not only transfers the doping material but also produces a local heating that promotes its diffusion into the substrate. The laser employed was a 1064 nm, lamp-pumped system, working at pulse durations of 100 and 400 ns. In order to obtain a good electrical performance a comprehensive optimization of the applied laser fluency and number of pulses was carried out. Subsequently, arrays of n + p local junctions were created by LIFT and the resultingl-V curves demonstrated the formation of good quality n+ regions. These structures were finally incorporated to enhance the front contact in conventional silicon heterojunction solar cells leading to an improvement of conversion efficiency. (C) 2014 Elsevier B.V. All rights reserved.