Novel Green Synthesis And Improved Solar-Blind Detection Performance Of ?-Ga₂O₃ Nanospheres

It is well known that the controllable synthesis,structure and performance characterization of Ga2O3 have attracted a wide range of interests in the study of nanoscale semiconductor materials,especially in the field of solar-blind detection,due to its extremely wide band gap.It has been reported that ?-Ga2O3,the most stable form of Ga2O3,possessed a high SBD activity due to its wide bandgap of 4.9 eV,indicating a great potential for SBD device applications.Recently,we found that metastable ?-Ga2O3 materials can exhibit a higher optoelectronic quality than ?-Ga2O3 with the similar structure,and especially that their photoelectric response levels depend on their structures.This prompted us to examine the possibility of further improving their SBD activity by decreasing their sizes and increasing their specific surface areas.This work is composed of two sections:1)The green controllable synthesis of ?-Ga2O3 nanospheres;2)The photoluminescence properties and improved solar-blind detection performance of gallium oxide materials.The first part involves the following details:The ?-Ga2O3 nanospheres which consist of primary nanoparticles with a diameter of about 10 nm were synthesized through hydrothermal method,showing an extremely high specific surface area(83.7 m2·g-1).The synthetic method has the advantages of being reliable and accessible,providing high reaction yields,monodisperse particles and phase homogeneity,and not requiring the use of organic solvents,templates and surfactants.Firstly,tartrate ions were coordinated with gallium ions to form gallium tartrate complex precursors in water,thereby efficiently suppressing the hydrolysis of Ga3+ ions to GaOOH.Secondly,this result emphasizes the importance of the slow hydrolysis of urea to produce OH-ions in improving the crystal growth of ?-Ga2O3.Lastly,gallium tartrate complex precursors directly converted to ?-Ga2O3 in the hydrothermal process.And the effects of reaction time,temperature and pH on the synthesis of ?-Ga2O3 crystals were also discussed.The second part involves the following details:The photoluminescence properties of similar structure of ?-Ga2O3 and different structure of ?-Ga2O3 were discussed.We foud that Ga2O3 show yellow-green and yellow emissions,which are mostly defect related.We investigated the solar-blind detection performance of?-Ga2o3 nanospheres and found that it has a specific response to 254 nm solar-blind light.Compared with ?-Ga2O3 nanomaterials with different morphologie and ?-Ga2O3 materials with similar morphology,the ?-Ga2O3 nanospheres possess improved solar-lind detection performance(eg,light current,1.83 ?A;light-dark ratio,2.29×103 and photocurrent fluctuation,<0.5%).