Preparation,Characterization And Photoelectric Properties Of 2D GaSe_xTe_1-x Micro-nanostructures

Two-dimensional layered materials with intriguing physical and chemical properties have recently attracted worldwide attention for their significant practical value and great prospect in the academic and industry community.Bandgap is one of the most important parameters determining the characteristics of the semiconductor materials,influencing its absorption and emission properties.However,there are very limited types of semiconductor materials present in nature.So it is particularly important to achieve the modulation of their bandgaps for a wide range of applications related to nano-electronic and optoelectronic devices.The alloy is a general method of regulating the band energy of a two-dimensional semiconductor material and it also regulates the lattice constant,valence band and conduction band position.Layered two-dimensional gallium-based chalcogenides compounds have the novel photonics and electronics properties and potentially wide applications.In this thesis,two-dimensional gallium-based chalcogenides with various special bandgap was simply synthesized through chemical vapor deposition method.Meanwhile,the nanodevices were successfully constructed.The photoconductivity performance was measured systematically.The main results are summarized as follows:?1?A series of two-dimensional GaSe_xTe_1-x?x=0¹?alloy nanomaterials with continuously tunable bandgaps from 1.7 eV?GaTe?to 2.15eV?GaSe?were synthesized by changing the molar ratios of raw materials.The available materials were characterized by SEM,EDS and Raman spectra.The samples were not the mixture of GaTe/GaSe and possess well-defined shape,high quality crystallization.We also characterized them with PL spectra,which range can be continuously from 628nm to756nm.?2?In this dissertation,we also reported the optoelectronic properties of 2D GaSe_0.5Te_0.5 nanodevice.The GaSe_0.5Te_0.5 nanoflakes were characterized by SEM,TEM,XRD,XPS,Raman and PL spectra to demonstrate the high crystal quality of as-prepared nanoflakes.The photodetector based on single GaSe_0.5Te_0.5 nanoflake shows fast response time,high reversibility and stability both in air and vacuum.The responsivity is up to 22AW^-1 and 13AW^-1 respectively under illumination of 532nm light and 650nm light.Moreover,compared to pure GaSe,the GaSe_0.5Te_0.5 nanoflake photodetector showed extended responsivity wavelength.These results suggest strongly that GaSe_0.5Te_0.5 nanoflakes hold great promises for future photodetector and photosensor application.