High energy electron irradiation effects on electrical properties of Au/n-ZnO Schottky diodes

High energy electron irradiation (HEEI) was performed on Au/n-ZnO Schottky diodes (SDs) and the effects of irradiation were compared with a reference SD. Current-voltage and capacitance-voltage measurements revealed that the barrier height and donor concentration decrease from 0.746 to 0.665 eV and from 4.55 x 10(14) cm(-3) to 1.76 x 10(14) cm(-3), respectively, while the ideality factor increases from 1.61 to 3.95 after irradiation. Ionization temperatures of traps were observed by means of thermally stimulated capacitance measurements at temperatures 307 K, 365 K and 332 K, 385 K and 477 K for the irradiated and the reference SDs, respectively. Deep level transient spectroscopy measurements revealed a defect level at 870 meV and capture cross sections of 0.88 x 10(12) cm(2) for the reference SD and two HEEI induced defects at energies 670 and 780 meV and capture cross sections of 29.6 x 10(-12) cm(2) and 3.08 x 10(-12) cm(2) for the irradiated SD, respectively.