Schottky rectifiers with implanted p/sup +/ guard ring edge termination fabricated on free-standing GaN substrates show reverse breakdown voltages up to 160 V in vertical geometry devices. The specific on-state resistance was in the range 1.7-3.0 /spl Omega//spl middot/cm/sup 2/, while the turn-on voltage was /spl sim/1.8 V. The switching performance was analyzed using the reverse recovery current transient waveform, producing an approximate high-injection, level hole lifetime of /spl sim/15 ns. The bulk GaN rectifiers show significant improvement in forward current density and on-state resistance over previous heteroepitaxial devices.