First-principles Study On InGaN With In-rich

With the development of the computer technology and thecomputational physics, using computer software to design and forecastthe physical and chemical properties of new materials attract people’sattention more and more. The theoretical calculation method of firstprinciples calculation has become an important physics research method.The lattice structure and the electronic properties of InGaN material areinvestigated in the paper by adopting first-principles density-functionaltheory calculations with the CASTEP code. The concentration of Ga stomis chosen0，0.04167，0.08333,0.125,0.16667,0.20833in the calculation.In addition, the influnce of atom interval point defect on the electronicproperties of InGaN material under In-rich conditions is calculated andanalyzed.The results show that the substitute Ga atoms for In atoms have thelowest formation energy under In rich conditions, and the formationenergy decrease slowly with the increasing the atom concentration. Theformation energy of Ga atomic interval defect is relatively high, and theformation energy of In atomic interval defect can be the highest. So Gaatom replace In atoms position in InN material during the process ofgrowing InGaN materials.The lattice constants of InGaN materialdecrease with increasing the Ga atoms concentration, the Vegard law is met better in the direction of C axis, but it is not met in the otherdirections. The pure InN material is a direct band-gap semiconductormaterial, and the InGaN materials that it is formatted by replacing Inatom with Ga atom is also a direct band-gap semiconductor material. Theanalysis of the states density shows that the main reason for leading to theband gap width is the interactions of doping Ga4S state electron and N2p state electron. With increasing the Ga atoms concentration, band gapof InGaN material also increase gradually, but the extent of the increaseis smaller than the extent of increasing Ga atoms concentration. Theinterval point defects study shows that In atom and Ga atom interval pointdefects lead to the broaden of band-gap of InGaN materials under In-richand the rise of corresponding energy of forbidden band. And the intervalpoint defects may be one of the reasons that the InGaN materials bandgap is broadened. By comparison, our results are an agreement with theexperimental and other theoretical results.