First-principles Study Of The Electronic Structure And Optical Properties Of GaN Nanowire Photocathodes

GaN photocathode,as one of the most crucial components in various optoelectronic devices such as ultraviolet photomultiplier,ultraviolet detector,has promising applications in numerous fields as public security,aerospace,high-energy physics,etc.However,little literature or investigation is reported so far regarding the use of GaN nanowires as photocathode material,so there exists large space for this exploration.In this paper,the first principles calculation method based on density functional theory(DFT)is used to explore the electronic structures and optical properties of GaM nanowires on a micro level,which provides theoretical guidance and theory foundation for the GaN nanowire photocathode production technology.This dissertation is divided into four parts as follows:The first part introduces the basic theories and analytical methods for the first principle theory,as well as some brief description about the CASTEP software package.The second part mainly introduces some researches on photocathode aspect of intrinsic GaN nanowires,including the computation convergence,the properties of GaN nanowire photocathode with various section sizes,and the effects of passivated surface atoms on GaN nanowire photocathode.In this part,a GaN nanowire photocathode model with large size and passivated H surface is selected for the whole analyses.The third part introduces some relevant studies on p-type doped GaN nanowire photocathode to exhibit the appropriateness of Mg for adopting element.In addition,a further study of Mg atoms adopted in various areas is demonstrated in this part about its effects on GaN nanowire photocathode properties,which shows great value to the production technology.The last part demonstrates the test results of N vacancy about its effects on properties of both GaN nanowire photocathode and Mg adopted GaN nanowire photocathode.Data indicates a potential hindrance of N vacancies to high-quantity GaN nanowire photocathode producing,and therefore makes clear the way for our future researches.