CVD Growth And Photoelectronic Properties Characterization Of GaSe Nanomaterial

The layered material gallium selenide is an important binary semiconductor.Because it has anisotropy,wide band gap and novel optical and electrical properties.These characteristics make gallium selenide having good applications prospects in solar cells,optical detector and integrated optoelectronics.In this case,we have synthesized a large number of high-quality gallium selenide nanobelts by self-catalytic chemical vapor deposition.The structure and properties of the materials were characterized by SEM,AFM,TEM,XRD,PL and Raman.Then we fabricated the GaSe nanobelt FET and tested its photoelectric properties.It shows the nature of the p-type semiconductor and the switch ratio of up to 10⁶.The gallium selenide nanobelt not only shows high response rate,but also shows good stability and reliability,which is superior to most of the peers.The main achievements are summarized as follows:?1?For the first time,we synthesis a large numner of high quality GaSe on SiO₂substrate with Ga and Ga₂Se₃ as a source.Through optical microscope,SEM and AFM tests,We can clearly see the as-grown nanobelt with smooth surface,the width range 1to 20 microns,length up to tens mm and the thickness about 100 nm.The XRD,TEM and EDX tests showed that the GaSe nanobelt we obtained was a hexagonal crystal phase with atomic ratio Ga:Se=1:1 and had a good crystal quality.The Raman scattering spectra and photoluminescence spectra of the single nanobelt are consistent with those of other groups,which further proves that the GaSe we obtained is of high crystallization quality.?2?Using the synthesized GaSe nanobelt as the material,nano-band photodetector is fabricated by means of high precision electron beam exposure and thermal evaporation.The test shows that the GaSe nanoband exhibits typical p-type semiconductor characteristics,which is consistent with previous reports.The field effect mobility is calculated to be 1.06 cm²·V^-1·s^-1,and the field effect transistor shows ultra-low leakage current?<1 pA?and high on-off ratio?10⁶?,Meanwhile,the GaSe nanobelt device shows good power dependent response properties under 520 nm laser illumination.The maximum R of the device can reach 164.4 A·W^-1,which is higher than that of the ever reported GaSe photodetectors(2200 mA·W^-1).Reliable and fast response speed is critical for photodetectors.The rise time and the decay time is calculated to be 0.26 s and 0.2 s,respectively.Such high performance in response is mainly attributed to the high quality of the GaSe single crystal,which can help decreasetheundesireddefect-inducedphoto-generatedelectron-holepairs recombination.All these performance parameters show that our detector has a great advantage than ever reports GaSe device.?3?On this basis,We synthesized large area GaSe thin film,and using SEM,AFM,TEM,PL,Raman test methods to obtain the properties of GaSe thin film.Experiments show that we get a large area of GaSe thin film with high quality.Large area of GaSe film has high application prospect in large scale integrated circuits.We also used In₂Se₃ to synthesize In_x Ga_1-x-x Se nanobelts,which realize the band gap regulation problem of nanobelt,and finally we obtained the In_0.1Ga_0.9Se nanobelt.These are groundbreaking jobs.It laid the foundation for our further research.