Aluminum induced crystallization of amorphous silicon thin films with assistance of electric field for solar photovoltaic applications

In this current research, the aluminum-induced crystallization of amorphous silicon (a-Si) was studied. Particularly, a-Si film covered with a very thin film of pure aluminum was exposed to a constant electrical voltage and high temperature. Every sample was subjected to annealing for 15 min with the application of an external electrical voltage. Nine treatments of different annealing temperatures and voltages were involved in this research. The levels of annealing temperature were 250 °C, 300 °C, and 350 °C, and the levels of external voltage were of 0 V, 2 V, or 20 V. After the annealing, the electrical, structural, and morphological properties of the a-Si layer have been investigated. Energy dispersive X-ray spectroscopy proved that there is diffusion of aluminum atoms inside the a-Si layer. X-ray diffraction showed that the crystallization depends on both temperatures and external voltage. We also noted that the electrical resistivity decreased significantly with annealing temperature and external voltage increasing. Moreover, the Hall mobility increased sharply with the increasing of annealing temperature and applied voltage, while the carrier concentration deceased slowly with increasing of both of them.