Femtosecond laser-induced simultaneous surface texturing and crystallization of a-Si:H thin film: morphology study

Abstract

Hydrogenated amorphous silicon (a-Si:H) thin films have been considered for use in solar cell applications because of their significantly reduced cost compared with crystalline bulk silicon; however, their overall efficiency and stability are less than that of their bulk crystalline counterparts. Limited work has been performed on solving the efficiency and stability issues of a-Si:H simultaneously. Surface texturing and crystallization on a-Si:H thin film can be achieved through one-step femtosecond laser processing, which can potentially alleviate the disadvantages of a-Si:H in solar cell applications. In this study, submicrometer con- ical and pillar-shaped spikes are fabricated by irradiating a- Si:H thin films deposited on glass substrates with hundreds of 800 nm-wavelength, 130 fs-duration laser pulses in air, and water environments, respectively. The formation mech- anisms for the surface spikes are discussed, and the differ- ences in the surface feature characteristics are also presented and explained within the context of the different processing environments. The effect of laser processing on light ab- sorption and crystallinity will be studied later.