Effect Of Localized Surface Plasmon Effect Of Ag Nanoparticles On The Performance Of Mix-structured MgZnO Solar Blind UV Detector

Recently,wide-bandgap semiconductor materials and wide-bandgap semiconductor based solar-blind UV detector have become a research hot topic in deep UV photoelectronic regain.Compared with other wide-bandgap semiconductor materials used in solar-blind UV detector,such as Al Ga N,Si C,Ti O2 and Ga2O3,Mg Zn O thin film materials possess many advantages,such as lattice matched substrate,high radiation hardness property,better stability,environment friendly,be rich on the earth,and so on.In addition,the Mg Zn O based UV detector own wider detectable UV range,relative higher UV response,lower noise and higher signal-to-noise ratio from the performance of UV detector,which makes Mg Zn O as an ideal material in high performance UV detector.This paper is focused on the improvement in performance of mixed-phase Mg Zn O based UV detector through adjusting the structure of Mg Zn O thin film and introducing the surface plasma effect,which are made according to recent develop situation of high-performance UV detectors.Firstly,the UV response characteristics of mix-phase Mg Zn O based UV detector with different structure distribution were studied.Then mix-phase Mg Zn O UV detectors were modified by Ag nanoparticles that made by two methods,vacuum-anneal and spin coating methods,and the effects of different size and density Ag nanoparticle on the performance of mix-phase Mg Zn O UV detectors were investigated.The main results of this paper are listed as follows:1.mixed-phase Mg Zn O films were deposited on the amorphous quartz substrate by PLD method,and the structure distribution in the Mg Zn O thin film was adjusted by different oxygen pressure,and the UV response characteristics of mix-phase Mg Zn O detectors with different structure distribution were studied.There are more hexagonal Mg Zn O in the mixed-phase Mg Zn O film deposited at higher oxygen pressure,and because the high resistance cubic Mg Zn O and low resistance hexagonal Mg Zn O distributed alternatively in the sample deposited at 3.3 Pa,the photo generated carriers experienced much more amplify times during their tunnel process between different structure Mg Zn O,the device has an optical response of 255 nm of 92.7 A/W under 25 V bias voltage.Because the dark current of the device is just 64 p A at 20 V bias voltage,the signal-to-noise ratio of the device reached 4 orders of magnitude.And because the change process between the normal state of the device in dark and the tunnel state of the device under UV condition is fast,the response rise time of the device is only 0.11 us,and the response drop relaxation time of which is just 0.026 ms.2.Ag nanoparticles(NPs)with different size were made by vacuum-anneal method,and the effect of different size Ag NPs on the UV response characteristics of mix-phase Mg Zn O UV detector were studied.By adjusting the diameter of Ag nanoparticles,introducing local resonance plasma with different resonance frequencies enhances the responsivity of the detector and reduces dark current.Increase the ratio of light to dark current.The Ag NPs with size around 20-40 nm could improve the response of the mix-phase Mg Zn O UV detector at 235 nm UV light from 0.1 A/W to 31.5 A/W under 25 V bias voltage,the deep UV response was improved by 288 times because of the localized surface plasma quaternary resonance effects,multi-level resonance effects and Rayleigh scattering effects of small size Ag NPs.3.30 nm Ag NPs with different density were made through the different layer's Ag NPs dispersion liquid by spin coting method,and the effect of the distribution density of Ag NPs on the UV response characteristics of mix-phase Mg Zn O UV detector was studied.As the density of 30 nm Ag NPs is higher with three layers Ag NPs dispersion liquid,the responsivity of the modified device at 300 nm UV light got great improvement by 33 times at 25 V bias voltage because of the bigger localized surface plasmon quaternary resonance effects of the Ag NPs,the dark current of the device don't increase by the Ag NPs,while the signal-to-noise ratio of the device was improved slightly.