Electrical losses induced by laser scribing during monolithic interconnection of devices based on a-Si:H

Abstract

A laser patterning process for the quantification of electrical losses in thin film cells and modules is presented. This work is focused on the first and the third laser patterning, P1 and P3 using UV (355 nm), IR (1064 nm) and visible wavelengths (532 nm) with pulse duration of a few ns. The change in electrical parameters and dependence of the laser scribing parameters, as film removal threshold, number of scribes, overlaps, with different sizes of scribes and metallic contact, have been studied for the requirements concerning the electrical characteristics for minimizing the electric losses in the scribe. The investigation is primarily carried out in single solar cells. Several optical imaging techniques and monitoring the electrical characteristics in the dark and illumination conditions are used to assess the quality of the P3 scribes. Finally, a-Si:H modules are fabricated using the optimum combination of P1 and P3 process parameters, with valour’s of efficiency among 5%.