Selective formation of large-grained, (100)- or (111)-oriented Si on glass by Al-induced layer exchange

By controlling the Si thickness and the annealing temperature used for Al-induced crystallization, we controlled the fraction of (100) and (111) orientations of polycrystalline Si (poly-Si) grains grown on glass. Changing the proportions of crystal orientation strongly influenced the average grain size of the poly-Si layer. By growing a 99% (111)-oriented poly-Si layer, formed with a 50-nm-thick Si layer at 375 °C, we produced a Si layer with grains nearly 40 μm in size. We discuss the growth mechanism from the perspective of competition between (100)- and (111)-oriented nuclei. This achievement holds promise for fabricating high-efficiency thin-film solar cells on inexpensive glass substrates