Effects Of Mg Doping On The Growth And Properties Of Ga₂O₃ Thin Films

Ga₂O₃ is a new type of wide bandgap semiconductor material,which has attracted the attention of more and more scholars in recent years.Ga₂O₃ owns a great application prospect in the fabrication of field effect transistors,solar blind photodetectors,transparent conductive electrodes,information memory,gas sensors,LED substrates and other devices due to its excellent physical properties?such as large band gap,large breakdown electric field strength,etc.?and good chemical stability.At present,the mainstream of gallium oxide semiconductor devices is thin film form,in order to obtain better performance of gallium oxide thin film,doping methods can usually be used to improve its porperties,which has also been proven to be an effective way by many researchers.Combined with the basic physical properties of gallium oxide material and the characteristics of Beijing University of Posts and Telecommunications,we studied the growth and properties of Mg-doped gallium oxide thin films with different structures in this thesis.The main contents are as follows:1.The Ga₂O₃ thin films with different Mg doping concentrations were prepared by L-MBE method on sapphire substrates.The properties of Ga₂O₃ thin films with different Mg doping concentration,such as surface appearance,elemental composition,optical properties and other characteristics were characterized.The results show that compared with the pure Ga₂O₃ thin film grown under the same growth conditions,the doped films swift from ? phase to ? phase,and the lattice constant and crystal quality also changed along the Mg concentration.In terms of optical properties,the absorption edge of the film is blue-shifted to about 205 nm.The optical bandgap is significantly increased up to 6 eV,and the bandgap of the film may be tuned from 4.9 to 7.8 eV by adjusting the doping concentration of Mg.Indicated that Mg doped Ga₂O₃ thin films is a promising material in the field of deep UV optoelectronic device.2.The Ga₂O₃/MgO/Ga₂O₃ thin films were deposite on the sapphire substrate by the L-MBE method,and then fabricated a heterojunction photodetector with Ti/Au electrodes on it to make the heterojunction photodetector by the magnetron sputtering method.The results show that the growth orientation of Ga₂O₃ grows on the?401?crystal plane on the MgO layer.The absorbance of the Ga₂O₃/MgO/Ga₂O₃ thin films in the visible region is larger than pure Ga₂O₃ thin film.The Ga₂O₃/MgO/Ga₂O₃ heterojunction photodetector has a lower dark current and a higher light/dark current ratio.