Preparation And Optoelectronic Properties Of Two-dimensional Gallium Tellurium And Selenide Compound Materials

Due to its unique layered structure,the two-dimensional material has caused the occurrence of quantum confinement effects.It has excellent optical and electrical properties,which has attracted widespread attention.Because of it's band gap width extending to visible light spectrum coverage and high light absorption coefficient advantages,it has great potential to be used in various fields such as photodetector s,catalysis,and energy.However,the controllable preparation of expected and large-area two-dimensional micron selenium materials is still a major problem that limits it's further research and application.Therefore,the controllable preparation of two-dimensional selenium-selenium compounds and the reduction of band gap are very strong.Taking GaTe,GaSe,GaSe_xTe_1-x as the research object,using chemical vapor deposition(CVD)to prepare GaTe,GaSe thin films and nanobelts,And the ternary GaSe_xTe_1-x nanobelt and the photoelectric properties were investigated.The specific work is as follows:(1)Using elemental gallium and Te powder as raw materials,the controllable growth of two-dimensional GaTe is realized by chemical vapor method.The influence of substrate,temperature,heating time and hydrogen ratio on the growth of two-dimensional GaTe is analyzed.The relationship between two-dimensional GaTe morphology and phase structure was explored,and it was found that two-dimensional GaTe with different phase structure ratios can be obtained through the control of growth temperature.In the growth of two-dimensional GaTe,this CVD method using elemental gallium liquid as a raw material highlights the advantage of rapid growth.Even with a holding time of 10 to 60 s,GaTe nanosheets of 5 to 30?m can be grown.Similarly,this method is used to achieve large-area growth of two-dimensional GaSe thin films.At a temperature of 750?and an air flow of 100 sccm,the lateral size of the GaSe thin film exceeds 1000?m.The thickness of the GaSe film grown by this method ranges from 1 to 6 nm,which is mainly affected by the heating temperature.According to photoluminescence spectroscopy(PL),the band gap decreases from 1.95 e V to 1.86 e V as the thickness decreases.(2)When growing the GaSe thin film,increase the temperature to 750?and reduce the proportion of hydrogen to 10 sccm.GaSe nanobelts formed by overlapping triangles end to end begin to appear on the substrate.The thickness of GaSe nanoribbons is about 4?6 nm,and the band gap is about 1.96 e V.It has high crystal quality and photoluminescence efficiency.A photodetector device is prepared based on GaSe nanoribbons.Under a voltage of 5 V,the device has a photoresponse current of 1.9?A,and the switch ratio reaches 13.03.(3)Choosing Ga₂Se₃,GaTe,and elemental gallium as growth materials,the ternary GaSe_0.8Te_0.2 nanobelt was synthesized by chemical vapor deposition.The GaSe_0.8Te_0.2 nanobelt has a Te percentage of 6.69,a band gap of 1.73 e V,and a thickness of about 20 nm.A photodetector device was prepared based on GaSe_0.8Te_0.2 nanoribbons.The dark current of the device under 0?,5 V bias voltage reached 20.38?A,the photoresponse current was 0.869?A,and it has good electrical conductivity and photoelectric response.And tested the change of the device performance under the temperature change of-125?0?.As the temperature decreases,the photoresponse current of the GaSe_0.8Te_0.2 nanobelt decreases,and the switching ratio gradually increases,which has a good application potential for optoelectronic devices.