title: Theoretical study on the structures and optical absorption of Si₁₇₂ nanoclusters.
abstract: The structures and optical properties of silicon nanoclusters (Si NCs) have attracted continuous interest in the last few decades. However, it is a great challenge to determine the structures of Si NCs for accurate property calculation due to the complication and competition of various structural motifs. In this work, a Si172 NC with a size of about 1.8 nm was investigated using a genetic algorithm combined with tight-binding and DFT calculations. We found that a diamond crystalline core with 50 atoms (1.2 nm) was formed in the Si172 NC. It can be expected that at a size of about 172 atoms, a diamond crystalline structure can nucleate from the center of the Si NCs. The optical properties of the pure and hydrogenated Si172 NC structures also have been studied using the TDDFT method. Compared with the pure Si172 NC, the absorption peaks of the hydrogenated Si172 NC are obviously blue-shifted.
authors.affiliation: Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, College of Physics, Qingdao University, Qingdao, Shandong 266071, P. R. China. qinw@qdu.edu.cn wencailu@jlu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Qin
authors.forename: Wen-Cai
authors.initials: WC
authors.lastname: Lu
authors.forename: Lin-Hua
authors.initials: LH
authors.lastname: Xia
authors.forename: Li-Zhen
authors.initials: LZ
authors.lastname: Zhao
authors.forename: Qing-Jun
authors.initials: QJ
authors.lastname: Zang
authors.forename: C Z
authors.initials: CZ
authors.lastname: Wang
authors.forename: K M
authors.initials: KM
authors.lastname: Ho