THE EFFECTS OF MICROCRYSTALLINE STRUCTURE ON THE PHOTOLUMINESCENCE OF POROUS SILICON-ON-SAPPHIRE

Silicon-on-sapphire was fabricated in as-deposited, improved, and bonded wafer forms. Each of the fabrication techniques imparts characteristic microcrystalline defects in the silicon layer. Microstructural defects such as microtwins and threading dislocations in the starting material have no observed effect on the light emitting properties of porous silicon-on-sapphire. Vacancies imparted by ion implantation damage, however, can amorphize the material resulting in a quenching of the photoluminescence (PL). An apparent increase in the density of light emitting structures leading to enhanced PL can also be obtained by limited ion damage of the material prior to the fabrication of the porous layer.