Research On Bandgap Adjustment Of Mg_xZn_1-xO Thin Films And Photoelectric Properties Of Ultraviolet Detectors

ZnO is a ?-? wide bandgap compound semiconductor material,and has received extensive attention due to its superior photoelectric properties.More importantly,by incorporating Mg in ZnO through a certain process,the bandgap of MgZnO can be adjusted to vary from 3.37 e V to 7.8 e V,covering the entire UV region,making MgZnO the preferred material for UV optoelectronic devices.However,there is a lattice mismatch between ZnO and MgO,phase separation occurs under certain components,and the band gap will change nonlinearly with the composition.How to achieve the effective adjustment of the MgZnO band gap and to prepare high-performance ultraviolet detectors on this basis has become a research hotspot in the field.At present,in order to achieve the controllable adjustment of the band gap of MgZnO in the ultraviolet region,molecular beam epitaxy,laser pulse deposition,chemical vapor deposition,and the like are mostly used.Compared with the above methods,magnetron sputtering technology has the advantages of low cost and easy large-area growth.In this paper,the bandgap adjustment of Mg_xZn_1-xO materials is achieved through patch co-sputtering technology,and the influence of Mg implantation on the crystal structure and optoelectronic pr operties of MgZnO crystals is studied.Based on the obtained results,a single-phase and mixed-phase MgZnO detection prototype device is designed and tested.Optical properties were analyzed.The main research content is as follows:Firstly,the process optimization of the bandgap adjustment of Mg_xZn_1-xO thin films with low Mg composition?Mg<30%?was carried out: the Mg_xZn_1-xO thin films with low Mg content were grown on quartz substrates by the co-sputtering method,and the process parameters were studied.The effect of the variation on the raw Mg implantation efficiency,film crystal quality,and optical performance shows that when the sputtering power is 140 W,the sputtering oxygen-argon ratio is 14:46,the sputtering pressure is 0.5 Pa,and the annealing temperature is 600 ?.The controllability of the injection efficiency of Mg is better.The band gap of MgZnO can be adjusted in the range of 3.82 e V-4.09 e V,and the film can maintain good crystal quality and optical performance.Secondly,the bandgap of high Mg Mg_xZn_1-xO thin film materials was adjusted in this paper.A series of Mg_xZn_1-xO thin films with different wide band gaps were grown on quartz.We found that the Mg_xZn_1-xO film bands increase with the increase of Mg content.The gap varied linearly with the magnesium content,and the band gap of ZnMgO was successfully adjusted in the range of 4.03 e V to 4.58 e V,and the film had good crystal quality and optical performance.Finally,the effects of annealing and buffer layer processing on the devic e performance were studied.The results show that annealing can improve the device response performance.For high Mg Mg component devices,the responsivity after annealing increases from 0.12×10^-3 A/W to 0.57×10^-3 A/W.In addition,we prepared Mg_xZn_1-xO devices with different Mg content.The response band of the device shifted to the short-wave direction with increasing Mg content.On this basis,we also studied the impact of the buffer layer ZnO on device performance.The spectral response of the Mg_xZn_1-xO based photoconductive device growing ZnO buffer layer has increased the device responsivity of the buffer layer from 0.12×10^-3 A/W to 0.43 A/W,an improvement of two orders of magnitude.It is illustrated that growing a buffer layer on quartz glass can improve the device's responsivity.