| In this work, we have grown ZnMgO films with different content of Mg on various substrates using PLD, and fabricated photoconductive UV detectors. For ZnMgO films with low content of Mg, we discussed the effect of the growth temperature, pressure, the time of temperature maintaining and the substrates on the characteristics of films. The time of temperature maintaining mainly affected the electronic properties. Films had better crystalline quality grown at higher temperature. But there would be Mg segregation if the temperature was too high. The influence of oxygen pressure was small, but the lattice distortion would increase if the oxygen pressure was too low.The quality of cubic MgZnO films with high content of Mg grown on SiO2 substrates was much poor than that of hexagonal films with low content of Mg. We fabricated c-MgZnO/h-ZnMgO bilayers using the ideas of homogenization buffer. The content of Mg was 19.9 at.%and 57.7 at.%for hexagonal and cubic films respectively. The quality of cubic MgZnO films with high content of Mg could be improved obviously through growing a layer of hexagonal films with low content of Mg. Cubic MgZnO films had small FWHM values and smooth surface. And the bilayers had obvious absorption edge. The band gap values were 4.0 eV and 4.82 eV for hexagonal and cubic films, respectively.Cubic MgZnO films with high content of Mg had the best crystalline quality, which were grown on MgO substrates at 400℃with oxygen pressure of 5Pa for 100 min. The band gap was 5.61 eV and the small value of RMS was only 1.0 nm.In the end, we fabricated ZnMgO based UV detectors with different Mg contents. The size of detectors was 6000μm×100μm×100μm×20(pairs). We found that the UV detectors had good ohmic contact. The dark current was about 10 nA under the bias voltage of 10 V. The cutoff wavelength of the UV detectors was 325 nm, which corresponded to the absorption edge of hexagonal ZnMgO films with low content of Mg. |
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