Admittance spectroscopy of electron irradiated p-type indium phosphide

Admittance spectroscopy measurements have been carried out on electron irradiated ITO/p-InP and Au/p-InP diodes, and their results have been compared with those obtained from I-V-T properties, deep level transient spectroscopy and thermally stimulated capacitance measurements. It was found that a high fluence of electron radiation, 10/sup 16/ cm/sup -2/ induces a dominant defect HD1 with a density of /spl sim/1.3/spl times/10/sup 16/ cm/sup -3/, much higher than that of defects H3 and H4. A further defect HD2 was also observed with a density of /spl sim/3/spl times/10/sup 15/ cm/sup -2/, which only appeared after annealing at T/sub A/>90/spl deg/C. It is defect HD1 which is held responsible for the removal of most carriers, the increase of series resistance and the subsequent degradation of solar cells, and not defects H3 and H4 as is normally accepted. Defect HD1 has a low threshold annealing temperature of /spl sim/70/spl deg/C, and is completely removed at 100/spl deg/C, more than 30/spl deg/C lower than that of defects H3 and H4.<
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