VERY HIGH-PURITY INP LAYER GROWN BY LIQUID-PHASE EPITAXY USING ERBIUM GETTERING

Very high purity InP layers have been grown by liquid phase epitaxy using rare-earth erbium as the donor-gettering source. All the Er-doped samples still exhibit n-type conduction, but its carrier concentration decreases with increasing the Er amount into the growth solution. The 300 K electron concentration as low as 7 X 10(13) cm-3 has been achieved on high-purity layers. By low-temperature photoluminescence measurement, the donor impurities of the InP samples have been obviously reduced due to the Er gettering. The free-exciton line with a linewidth of 0.9 meV dominates in the exciton spectra and the intensity ratio of free exciton to exciton-bound-to-neutral-donor lines exceeds 2.6 for the high-purity layers with n = 7 X 10(13) cm-3.