Chemical surface passivation of 3C‐SiC nanocrystals: A first‐principle study

Abstract

The effect of the chemical surface passivation, with hydrogen atoms, on the energy band gap of porous cubic silicon carbide (PSiC) was investigated. The pores are modeled by means of the supercell technique, in which columns of Si and/or C atoms are removed along the [001] direction. Within this supercell model, morphology effects can be analyzed in detail. The electronic band structure is performed using the density functional theory based on the generalized gradient approximation. Two types of pores are studied: C-rich and Si-rich pores surface. The enlargement of energy band gap is greater in the C-rich than Si-rich pores surface. This supercell model emphasizes the interconnection between 3C-SiC nanocrystals, delocalizing the electronic states. However, the results show a clear quantum confinement signature, which is contrasted with that of nanowire systems. The calculation shows a significant response to changes in surface passivation with hydrogen. The chemical tuning of the band gap opens the possibility plenty applications in nanotechnology.

Surface-state dependent optical properties of OH-, F-, and H-terminated 4H-SiC quantum dots

“…Figure 5 show the ACS for C-centered SiC-QDs. The relatively small differences between the Si and C centered structures are most likely a consequence of the differing mixtures of C-H and Si-H bonds at the surface 40,41 , as previous studies report QDs with Si-H surface bonds exhibit smaller energy gaps compared to C-H surface 35,36,42,54 . Although there are minor differences, the overall trends for Ccentered SiC-QDs are very close to those of the Si-centered clusters shown in Fig.…”

Calculation of lattice vibrational and thermal properties of cadmium sulfide nanocrystal and growth preference of cadmium sulfide powder during microwave‐hydrothermal process

“…The GGA in the Perdew-Burke-Eruzerh (PBE) [34][35][36] and the Hubbard U correction [37] were adopted to calculate lattice vibrations and thermal properties of CdS. The commonly used Cambridge Sequential Total Energy Package and WIEN2k package [38] were selected based on DFT calculations.…”

Fluorinated porous silicon as sensor material for environmentally toxic gases: a first-principles study

“…5,[27][28][29][30] In a similar way, surface chemistry has been proved to modify the electronic structures and optical behaviour of semiconductors. 31 Hydrogen passivation causes a transition from metallic to semiconducting behaviour in Si nanowires 32,33 and band gap changes in another Si nanostructures. [34][35][36][37] Previous studies show that single-bonded atoms on Si surfaces, for example, Cl and F, may lightly diminish the energy bandgap.…”