Cu掺杂硅量子点的电子结构和光学性质

Electronic Structures and Optical Properties of Cu-doped Silicon Quantum Dots

采用基于密度泛函理论的第一性原理的方法,对Cu掺杂H钝化硅量子点的形成能、态密度、磁性和光学性质进行了计算,考虑了Cu占据硅量子点替代和间隙的不同位置。结果表明:Cu趋向占据硅量子点表面的六角形间隙位置。Cu掺杂硅量子点引入了杂质能级,带隙变窄。由于Cu的d态p态和Si的p态耦合,导致Cu替代掺杂硅量子点具有铁磁性,且在低能区出现了一个较强的吸收峰。

The formation energies,density of states,magnetic properties and optical properties of hydrogen-passivated Cu-doped silicon quantum dots were calculated by first-principles based on density functional theory.The substitutional sites and the interstitial sites were considered.The results show that Cu preferentially occupy an interstitial position with hexagonal symmetry near the surface of silicon quantum dots.The doping of silicon quantum dots with Cu introduces impurity level in near Fermi level.The interstitially doping and substitutionally doping of silicon quantum dots with Cu,the density of states near Fermi level is mainly contributed by Cu s orbital and Cu d orbital p orbital and Si p orbital,respectively.For substitutionally doping and hexagonal interstitially doping,a ferromagnetic behavior is observed.A strong absorption peak occurs in the low-energy region of substitutionally doping of silicon quantum dots with Cu.