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.