Research paper A computational study on semiconducting Si 60 , Si 59 Al and Si 59 P nanocages Ambrish Kumar Srivastava a , Sarvesh Kumar Pandey b , Neeraj Misra c,⇑ a P.G. Department of Physics, Veer Kunwar Singh University, Ara, Bihar 802301, India b Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016, India c Department of Physics, University of Lucknow, Lucknow, Uttar Pradesh 226007, India article info Article history: Received 5 August 2017 In final form 1 November 2017 Available online 2 November 2017 Keywords: Silicon fullerenes Nanostructures Semiconductivity DFT calculations abstract We performed density functional theory based calculations on Si 60 cage and analyzed the effect the sub- stitution of single Al or P atom. We have explored and compared various electronic properties of Si 60 , Si 59 Al and Si 59 P cages. The density-of-state curves reveal that the substitution of Al (or P) creates addi- tional energy level such that the frontier orbital gap is decreased, increasing its conductivity. The lower ionization energy of Si 59 Al and higher electron affinity of Si 59 P suggest the easy injection of holes and electrons, respectively. These findings clearly demonstrate that Si-nanoclusters mimic the properties of their bulk analogues. Ó 2017 Elsevier B.V. All rights reserved. 1. Introduction Silicon (Si), due to its widespread application in semiconductor devices, is an element of fundamental interest. Found just below carbon (C) in the periodic table, Si-nanostructures have been paid much attention after the discovery of C 60 [1]. Small Si n clusters (n < 60) have been widely studied theoretically [2–7] as well as exper- imentally [8–10]. Doped and substituted Si-clusters have been reported to possess many interesting properties. The magnetic properties of a metal-encapsulating Eu@Si 20 fullerene like cage [11] and perfectly symmetric M@Si 20 H 20 (M = Co, Ti, V, and Cr) [12] cages indicate their possible applications in the fields of spin- tronics and high-density magnetic storage. The stability of Si N Pt N/2 (N = 20–60) based exohedral cages has been found to be equivalent to carbon fullerenes (C N ) [13]. Si 60 C 60 fullerene like cage has been studied for its hydrogen storage capacity [14] and Si 10 H 16 cluster has been noticed for its lithium storage capacity [15]. Moreover, Si-nanostructures have been also recognized for their photonic and photovoltaic applications [16]. Analogous to C 60 , several attempts have been made to explore the structure and properties of Si 60 [17–20]. It has been noticed in case of C 60 [21] that a single B or N atom can change the electron transport properties such that C 59 B fullerene can be an effective semiconductor in p-type devices. It seems, therefore, interesting to analyze whether Si 60 behaves similar to that of C 60 , i.e., whether Si 59 Al and Si 59 P cages mimic the properties of p-type and n-type semiconductors at nanoscale. Note that the fundamental semicon- ductor physics [22] is based on the fact that the conductivity of pure (bulk) silicon is significantly increased by doping of trivalent (B, Al etc.) or pentavalent (P, As etc.) impurities. Likewise, these semiconductors behave as p-type or n-type depending on the nat- ure of impurity. In p-type semiconductor, holes are treated as the majority charge carriers, whereas in n-type semiconductors, majority carriers are electrons. In this study, we attempt to show that these characteristics are also observed at the nanoscale. We have considered pure Si 60 cage and substituted single Al as well as P atom on Si 60 . Using density functional theory (DFT), we have computed and compared electronic properties of Si 60 , Si 59 Al and Si 59 P. One of the primary objectives of this study is to demonstrate how the finite-sized Si-clusters mimic the properties of their bulk analogues. 2. Computational details This computational study has been performed using B3LYP method with 6-31G(d) basis set as implemented in GAUSSIAN 09 program [23]. This computational scheme has been extensively used for the study of C 60 and related systems [24–28]. The hybrid B3LYP exchange-correlation functional incorporates Becke’s three parameter exchange term [29] and correlation term of Lee, Yang and Parr [30]. The 6-31G(d) is a valence double-zeta polarized basis set in which six primitive Gaussian functions are used for core atomic orbitals and valence orbitals are two basis functions https://doi.org/10.1016/j.cplett.2017.11.001 0009-2614/Ó 2017 Elsevier B.V. All rights reserved. ⇑ Corresponding author. E-mail address: mishra_neeraj@lkouniv.ac.in (N. Misra). Chemical Physics Letters 691 (2018) 82–86 Contents lists available at ScienceDirect Chemical Physics Letters journal homepage: www.elsevier.com/locate/cplett