Formation Of P-N Homojunctions In N-Zno Bulk Single Crystals By Diffusion From A Zn3p2 Source

p-n junctions have been formed in lightly n-type (10(17) cm(-3)) bulk, single-crystal ZnO substrates by diffusion of P from a Cd3P2, arsenic and red phosphorous dopant source in a closed-ampoule system. The P incorporation depth was found to be similar to 200 nm after diffusion at 550 degrees C for 30 min, as determined by secondary ion mass spectrometry profiling. The resulting structures show rectification, with on-off current ratios of similar to 70 at + 3/-5 V. The forward current ideality factor was >= 2, consistent with multiple current transport mechanisms present in the junction, such as defect-assisted tunneling and conventional carrier recombination in the space-charge region via midgap deep levels. The forward turn-on voltage, V-F was similar to 4 V at 300 K with a specific on-state resistance (R-ON) of similar to 21 m Omega cm(2). The activation energy of the forward current at low forward biases was similar to 1.4 eV. This is also consistent with carrier recombination in the space charge region via a midgap deep level. (c) 2005 American Institute of Physics.