Enhanced photoresponse performance in Ga/Ga_2O_3 nanocomposite solar-blind ultraviolet photodetectors

In the present work, we explore the solar-blind ultraviolet(UV) photodetectors(PDs) with enhanced photoresponse,fabricated on Ga/Ga_2O_3 nanocomposite films. Through pre-burying metal Ga layers and thermally post-annealing the laminated Ga2 O3/Ga/Ga_2O_3 structures, Ga/Ga_2O_3 nanocomposite films incorporated with Ga nanospheres are obtained. For the prototype PD, it is found that the photocurrent and photoresponsivity will first increase and then decrease monotonically with the thickness of the pre-buried Ga layer increasing. Each of all PDs shows a spectrum response peak at 260 nm, demonstrating the ability to detect solar-blind UV light. Adjustable photoresponse enhancement factors are achieved by means of the surface plasmon in the nanocomposite films. The PD with a 20 nm thick Ga interlayer exhibits the best solar-blind UV photoresponse characteristics with an extremely low dark current of 8.52 p A at 10-V bias, a very high light-to-dark ratio of ～ 8 × 10~5, a large photoresponsivity of 2.85 A/W at 15-V bias, and a maximum enhancement factor of ～ 220. Our research provides a simple and practical route to high performance solar-blind UV PDs and potential applications in the field of optoelectronics.     

Temperature dependence of Cu2O orientations in the oxidation of Cu（111）/ZnO（0001） by oxygen plasma

The role of temperature on the oxidation dynamics of Cu2O on ZnO (0001) was investigated during the oxidation of Cu (111)/ZnO (0001) by using oxygen plasma as the oxidant. A transition from single crystalline Cu2O (111) orientation to micro-zone phase separation with multiple orientations was revealed when the oxidation temperature increased above 300°C. The experimental results clearly show the effect of the oxidation temperature with the assistance of oxygen plasma on changing the morphology of Cu (111) film and enhancing the lateral nucleation and migration abilities of cuprous oxides. A vertical top-down oxidation mode and a lateral migration model were proposed to explain the different nucleation and growth dynamics of the temperature-dependent oxidation process in the oxidation of Cu (111)/ZnO (0001).     

Temperature dependence of Cu20 orientations in the oxidation of Cu （111）/ZnO （0001） by oxygen plasma

The role of temperature on the oxidation dynamics of Cu20 on ZnO （0001） was investigated during the oxidation of Cu （111）/ZnO （0001） by using oxygen plasma as the oxidant. A transition from single crystalline Cu20 （111） orientation to micro-zone phase separation with multiple orientations was revealed when the oxidation temperature increased above 300 ~ C. The experimental results clearly show the effect of the oxidation temperature with the assistance of oxygen plasma on changing the morphology of Cu （111） film and enhancing the lateral nucleation and migration abilities of cuprous oxides. A vertical top-down oxidation mode and a lateral migration model were proposed to explain the different nucleation and growth dynamics of the temperature-dependent oxidation process in the oxidation of Cu （lll）/ZnO （0001）.