New semiconducting silicide Ca₃Si₄

Abstract

By means of ab initio calculations we have revealed a newly discovered Ca3Si4 compound to be a semiconductor. It is characterized by an indirect transition of 0.35 eV. A peculiar dispersion of the last valence band and the first conduction band, displaying a loop of extrema, has been found. This feature leads to large anisotropy of the mobility of holes and electrons. We also present the dielectric function of this material in comparison with data for another semiconducting calcium silicide Ca2Si.

First-principle studies of Ca–X (X=Si,Ge,Sn,Pb) intermetallic compounds

“…Therefore, Ca 3 Si 4 is an indirect band gap semiconductor, and the result is in a fairly good agreement with the discovery reported in Ref. [4]. As for other intermetallics considered in the 20 compounds, their valence band overlaps the conduction band at the Fermi surface in the diagrams.…”

“…Among these intermetallic compounds, Ca-X (X= Si, Ge, Sn, Pb) system intermetallic compounds have drawn considerable attention owing to their practical applications in thermoelectric and optoelectric materials and in the design of novel electronic devices [4,5]. Based on earlier results, phase diagrams of Ca-X systems have been investigated by Manfrinetti [6], Palenzona [7,8], Okamoto [9] and Bruzzone [10].…”

“…For example, various aspects such as structural properties [5][6][7][8][9][10]13], energy band structures [5], electronic densities of states [5], dielectric functions [5], and heats of formation [11,12,14] have been explored systematically. As a newly discovered compound Ca 3 Si 4 , its structural properties, energy band structures, transport properties and dielectric functions have been studied by Manfrinetti and Migas et al It has been found that Ca 3 Si 4 is an indirect band gap semiconductor with a band gap of 0.35 eV [4,6]. Moreover, it has been reported that Ca 5 Si 3 and CaSi can emerge as promising candidates for hydrogen storage materials [15].…”

Preparation of Ca-Si Films on (001) Al2O3 Substrates by an RF Magnetron Sputtering Method and Their Electrical Properties

“…On the other hand, the Ca 3 Si 4 phase was reported to be synthesized using a long postannealing after quenching from the liquid phase 10 or forming a Si/Ca 3 Si 4 /(111)Si structure using a layer-by-layer deposition technique. 11 These reports suggest that a special technique may be essential to prepare films with a Ca 3 Si 4 single phase. Figure 4 is a cross-sectional SEM image of a Ca 5 Si 3 film with a Ca/Si ratio of 1.73.…”

First-principles investigation of the thermo-physical properties of Ca3Si4

“…For Ca 3 Si 4 , the detailed crystal information has been determined [9]. From first-principles calculations [10][11][12], Ca 3 Si 4 is a semiconductor with indirect band gap. The band energy gap of Ca 3 Si 4 has been predicted as indirect band gap with 0.598 eV [10], 0.35 eV [11], and 0.375 eV [12], respectively.…”