Effects of plasma conditions on properties of ZnO films grown by plasma-assisted molecular beam epitaxy

The influence of rf power and aperture plate configuration on the growth of ZnO thin films using plasma-assisted molecular beam epitaxy was investigated. It was found that by changing the aperture plate geometry from 276 to 25 holes, an increase of growth rate was observed, suggesting that the latter is more efficient for ZnO growth. The structural, electrical, and optical properties were also improved as measured by in situ electron diffraction, single field Hall, effect, and photoluminescence. A background carrier concentration of 1 x 10(18) cm(-3) and a mobility of 52 cm(2)/V s were measured, and a room-temperature band edge peak 200 times the defect band intensity was observed. Optical emission spectroscopy shows significantly different behavior in plasma generated using the two plates and suggests that more than increased atomic oxygen production is occurring. (c) 2006 American Vacuum Society.