Pulsed Laser Melting Effects on Single Crystal Gallium Phosphide

We have investigated the pulse laser melting (PLM) effects on single crystal GaP. The samples have been studied by means of Raman spectroscopy, glancing incidence X-ray diffraction (GIRXD), van der Pauw and Hall effect measurements. After PLM process, the Raman spectra of samples annealed with the highest energy density show a forbidden TO vibrational mode of GaP. This suggests the formation of crystalline domains with a different orientation in the GaP PLM region regarding to the GaP unannealed region. This behavior has been corroborated by glancing incidence x-ray diffraction measurements. A slightly increase in the sheet resistivity and a suppression of the mobility in PLM samples have been observed in all the measured temperature range. Such annealing effects are a cause of great concern for intermediate band (IB) materials formation where PLM processes are required first, to recovery the lattice crystallinity after high dose ion implantation processes and second, to avoid impurities outdiffusion when the solid solubility limit is exceeded.