(中南大學(xué) 資源加工與生物工程學(xué)院，長沙 410083)
摘 要: 采用基于密度泛函理論框架下的第一性原理平面波超軟贗勢法，研究Cu、Ni單摻雜與共摻雜體系中FeS2的晶體結(jié)構(gòu)、電子結(jié)構(gòu)和光學(xué)性質(zhì)。結(jié)果表明：摻雜后黃鐵礦發(fā)生晶格畸變，晶格常數(shù)變大，摻雜在FeS2禁帶中引入雜質(zhì)能級，使禁帶變窄，費米能級上移進入導(dǎo)帶，摻雜黃鐵礦的態(tài)密度穿過費米能級，形成簡并半導(dǎo)體，體系的導(dǎo)電率增強。光學(xué)性質(zhì)計算表明：摻雜后介電函數(shù)虛部主峰、吸收系數(shù)和光電導(dǎo)率均出現(xiàn)紅移、峰值減小。共摻雜后的光躍遷強度明顯增強，可見光區(qū)范圍內(nèi)的光吸收系數(shù)和光電導(dǎo)率均增大，說明Cu-Ni共摻雜顯著增強FeS2對光的吸收以及光電轉(zhuǎn)換效率。
關(guān)鍵字: Cu-Ni摻雜；FeS2；光學(xué)性質(zhì)；第一性原理計算
（School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China）
Abstract:The crystal and electronic structures, optical properties of copper and nickel mono- and co-doped FeS2 were studied by the ？rst-principles plane-wave ultrasoft pseudopotential method with the generalized gradient approximation. The results show that, the lattice deformation of FeS2 occurs and the lattice parameters increase after doping. And the impurity energy level is introduced by Cu and Ni doping, which also leads to decrease of the band gap of FeS2. Fermi levels moves upward and into conduction band and density of states traverses the Fermi level, indicating that the doped FeS2 is degenerate semiconductor which shows stronger metallic characteristic and electrical conductivity. In addition, the doping results in peaks redshift and amplitudes decrease of imaginary part of dielectric function, absorption coefficient and conductivity. Optical transition is significantly enhanced and so are absorption coefficient and conductivity within visible region in the co-doping system. The photoabsorption capacity and photoelectrical efficiency of FeS2 are highly strengthened in Cu-Ni co-doping system.
Key words: Cu-Ni doping; FeS2; optical property; ？rst-principles calculation
