Research On Crystal Phase,Carrier Regulation And Solar Blind Detector Of Doped Ga₂O₃ Thin Films

As a new type of direct band gap band gap semiconductor,gallium oxide is mainly used in photodetectors,gas sensors,information storage and crystal field effect tubes,which have attracted great interest in recent years.Because gallium oxide has 5 isomers,namely,alpha,beta,gamma,delta and epsilon,it is very important to study each phase of gallium oxide.Elemental incorporation is an important way to obtain metastable phase and control physical properties.In this paper,the crystal structure and carrier transport properties of doped gallium oxide film are systematically studied,which provides a theoretical basis for enhancing the performance of gallium oxide solar blind detector.The main results are as follows:(1)the crystal structure of gallium oxide films is influenced by doped elements and effect of grain size,while the grain size is mainly affected by the growth parameters,it was found that when increase the growth temperature and oxygen partial pressure or the decrease of pulse frequency,gallium oxide thin films change from the beta to epsilon,by calculating the critical size of beta phase and epsilon phase is about 40 nm.(2)Ga2-xSnxO3 films with different phases were prepared by laser molecular beam epitaxy.Because of there are 4 electronic around tin atoms,when the tin atoms replace gallium will generate electronic,thus serving as a donor to replace gallium,make Ga2-xSnxO3 a n type semiconductor,the results found that when x is 0.25,the best performance of conductive beta-Ga2-xSnxO3 thin film.This result also provides a theoretical basis for the preparation of beta-Ga2-xSnxO3 solar blind detectors.In addition,alpha-Ga2-xSnxO3 film prepared when x was 0.6,while the growth process of the oxygen partial pressure increasing,divalent tin ions will gradually produce,resulting in impurity compensation effect with stannic ion.(3)On the basis of the successful preparation of Ga2-xSnxO3,using Au/Ti as interdigitated electrode.When 254 nm light is used,it is found that the performance of beta-Ga2-xSnxO3 and alpha-Ga2-xSnxO3 is better than that of the pure gallium oxide solar blind detector,the photoelectric responsivity is increased and the relaxation time constant is decreased.In addition,due to the large dark resistance of the prepared epsilon-Ga1.8Sn0.2O3,it is very beneficial for the design of epsilon-Ga1.8Sn0.2O3 solar blind detector.(4)The Ga2-xZnXO3 film was prepared and the PL spectra of the thin films were measured at different concentrations.The results showed that the PL spectral intensity of the thin films increased gradually when x=0 to x=0.8,while the PL spectral intensity of the thin films weakened when x=1.0,which was caused by the concentration annihilation effect.The solar blind photodetectors are prepared by Ga1.2Zn0.8O3.The results show that the performance of the solar blind detector is higher than that of the pure gallium oxide,the photoelectric response is enhanced and the relaxation time constant is reduced.