Aluminum-Induced Crystallization of Hydrogenated Amorphous Silicon Thin Films With Assistance of Electric Field for Solar Photovoltaic Applications

In this work, the aluminum-induced crystallization of hydrogenated amorphous silicon (a-Si:H) has been investigated. Specifically, constant temperature and voltage were applied on a-Si:H films covered with a very thin layer of pure aluminum. Each sample was subjected to annealing for 15 minutes while connected to an external electrical power. Nine different treatments of annealing temperatures and voltages were included in this study. The levels of applied voltages were 0 V, 2 V, or 20 V, and the levels of annealing temperatures were 200 °C, 250 °C, and 300 °C. The electrical, morphological, and structural properties of the treated a-Si:H layer were studied. The results of energy dispersive X-ray spectroscopy showed a diffusion of aluminum atoms inside the a-Si:H layer. While, X-ray diffraction revealed that the crystallization depends on both the annealing temperature and the external voltage. Moreover, the obtained results showed that the electrical resistivity decreases considerably, the carrier concentration deceases slowly, while the Hall mobility increases sharply with increasing the annealing temperature and the applied voltage.