The formation energies,electronic structures and optical properties of Ti-doped silicon nanocrystals were calculated by first-principles based on density functional theory.We considered configurational characteristics of the substitutional sites and the interstitial sites.The results show all of the sites are energetically unfavorable,and Ti atoms setting in the center tetrahedron interstitial position of Si nanocrystals implies the energetic balance closest to the eguilibrium.The 3d orbits of Ti split into t2g triplet and eg doublet.It is observed that substitutional Ti causes eg manifolds to appear inside the band gap.However,they cannot produce by themselves any donor level because they are empty.Interstitial Ti causes the partially filled t2g manifolds to appear inside the band gap.An impurity band fulfilling all the requirements of an intermediate-band material is formed in the silicon nanocrystals.The imaginary parts of dielectric function and optical absorption on interstitially Ti show that the doping can strengthen the absorbing intensity of solar spectrum lower than 3 eV.
LIANG Weihua
,
HAO Dongning
,
DING Xuecheng
,
GUO Jianxin
,
WANG Yinglong
. Effects of Ti-doped on structures and optical properties of silicon nanocrystals[J]. Journal of Hebei University(Natural Science Edition), 2017
, 37(3)
: 231
-236
.
DOI: 10.3969/j.issn.1000-1565.2017.03.002
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