Confinement effects of phosphorus donors embedded in silicon microcrystals

Due to their extended electronic structure shallow donors are believed to b e very sensitive to confinement effects. Our interest is to investigate the influence of size on the properties of shallow donor phosphorus in mechani cally milled silicon microcrystals. The crystallinity of powders is confirm ed by X-ray diffraction and the size as determined by scanning electron mic roscopy was found to be 0.25 mu m for smallest to 4 mu m for largest microc rystals. In the current experiment we use electron paramagnetic resonance t o measure the hyperfine interaction between donor electron and P nucleus. T he hyperfine constant and mutual overlap of donor wave functions exhibit si gnificant dependence on grain size and subsequent annealing. By photolumine scence spectroscopy the appearance of a strong band around 1515 nm which sh ifts to higher energies with diminishing grain size has been established.