First Principles Study Of The Photoelectric Properties Of Al,Si Poped CdSe

Cadmium selenide?Cd Se?has become one of the widely used compounds semiconductor materials with its excellent photoelectric properties.Wurtzite CdSe is an important kind of room temperature detector material.To increase the use of Wurtzite CdSe,and expand its applications,it's necessary to regulate the optical belt gap of the CdSe and modify its conduction type.In this paper,the electron structure and optical property of the Al/Si doped wurtzite CdSe were studied,by the method of the plane-wave pseudo potential of the first principles under the density functional theory.Here are the results:?1?The formation of Cd_0.9722Al_0.0278Se supercell,Cd_0.9722Si_0.0278Se supercell and Cd_0.9444Al_0.0278Si_0.0278Se supercell are calculated,the results showed that the stability of Cd_0.9722Al_0.0278Se supercell was the best.The formation of Cd_0.9722Si_0.0278Se supercell was the largest,so,it's has the worst stability..?2?When impurities are added,the band gap of the systems is reduced,and the Fermi level enters conduction band,systems is converted from n-type semiconductor to n-type degenerate semiconductor.Compared with Si doped wurtzite CdSe system and Al/Si co-doped wurtzite CdSe system,the bond cooperation between impurity atom and Se atom is the strongest for Cd_0.9722Al_0.0278Se supercell,the system is the most stable for Cd_0.9722Al_0.0278Se supercell,consistent with the formation energy analysis.?3?The highest resistance of Si doped CdSe was calculated,followed by Al doped CdSe and Al/Si co-doped CdSe;Al/Si co-doping system of the minimum optical band gap is the largest,followed by Al mono-doping system and Si mono-doping system.The larger optical band gap and higher resistance to improve wurtzite CdSe detection performance,coupled with stability,Al doped CdSe is more suitable for detecting material.?4?The absorption regions are concentrated in ultraviolet region,both before and after doping.When impurities are incorporated,the absorption strength of CdSe is weaker,and the absorption spectrum has a red-shift to lower energy direction.the impurities have a great influence for CdSe on the refractive index in the visible and infrared regions,the maximum energy loss in the ultraviolet region was sharply reduced,and the energy loss of the Al/Si co-doped CdSe was the least.In the ultraviolet region,particularly in the al-si system,it has low absorption and reflectivity,which actually shows the high permeability of the ultraviolet region.In general,Al/Si doping for wurtzite CdSe on ultraviolet material research and development has significant guiding.