The effect of substrate temperature and source flux on cubic ZnMgO UV sensors grown by plasma-enhanced molecular beam epitaxy

Cubic ZnMgO films were grown by plasma-enhanced molecular beam epitaxy on MgO substrates. Interdigitatal metal–semiconductor–metal contacts were fabricated with Ni/Mg/Au to investigate the effect of growth temperature and source flux ratio on UV sensor properties. Device spectral responsivity was found to decrease with increasing Mg content, while UV–visible rejection ratio correspondingly increased. Peak responsivities ranged from 236 nm to 260 nm, spanning from 10 mA/W in the single crystal, high Mg case to ∼500 A/W for phase segregated films. UV–visible rejection ratios increased with increasing Mg content to three orders of magnitude. Solar blind detectors were realized with single-crystal ZnMgO, while effective visible blind detectors were made with phase-segregated ZnMgO films.