writer：Wei Qin*, Wen-Cai Lu*, Li-Zhen Zhao, K.M. Ho, C.Z. Wang
keywords：optical absorption，Ge nanoparticles
source：期刊
specific source：Computational Materials Science 140, 148(2017)
Issue time：2017年
The optical absorption properties of non-crystalline and crystalline Ge nanoparticles with the sizes from ～2.5 to 15 ? have been studied at the B3LYP/6-31G level using time-dependent density functional theory. Hydrogen passivation and phosphorus doping on some selected Ge nanoparticles were also calculated. With the increase of cluster size, the optical absorption spectra of the non-crystalline Ge nanoparticles change from many peaks to a continuous broad band and at the same time exhibit a systematic red-shift. Doping phosphorus also causes the absorption spectra to shift toward the lower energy region for both non-crystalline and crystalline Ge nanoparticles. The non-crystalline Ge nanoparticles are found to have stronger absorption in the visible region in comparison with the crystalline ones, regardless phosphorus doping.