Yellow luminescence from precipitates in GaN epilayers

In this work, the excimer-laser-induced crystallization of a-Si films on SiO₂ was investigated using a long-pulse-duration (200 ns) XeCl source. The microstructural analysis of the laser-irradiated area, for incident energy densities comprised between the thresholds corresponding to the surface and full melting, respectively, of the Si layer, was performed by scanning electron microscopy and Raman spectroscopy. A super-lateral-growth regime was evidenced quite comparable to that which occurs when classical excimer laser pulses of short duration (≈20 ns) are used. A numerical simulation of the surface melt dynamics was also performed and compared to the experimental observations. Received: 8 February 1999 / Accepted: 15 February 1999 / Published online: 5 May 1999