Growth of ZnO films on C-plane (0 0 0 1) sapphire by pulsed electron deposition (PED)

Thin films of ZnO on C-plane (0 0 0 1) sapphire (α-Al2O3) substrates were grown by pulsed electron beam deposition (PED). Intense electron pulses, approximately 0.8 J/70 ns pulse produced by a channelspark pulsed electron source at a rate of 10 Hz were used to ablate sintered polycrystalline ZnO targets at an oxygen pressure of 15 mTorr. During growth, the sapphire substrate temperature was maintained at 700 °C. A 15 min growth produced a 250 nm film, as measured by a Dektak profilometer. Measurements by X-ray diffraction indicate c-axis oriented films. Cathodoluminescence (CL) data show strong band edge emission. Optical absorption data indicate a sharp band edge with clearly visible exciton absorption at room temperature, and resolved A and B excitons at 77 K. Thus, pulsed electron beam deposition of ZnO films is shown to be a viable technique for producing high quality ZnO films.