TY - JOUR
T1 - Computational simulation of the effects of oxygen on the electronic states of hydrogenated 3C-porous SiC
AU - Trejo, Alejandro
AU - Calvino, Marbella
AU - Ramos, Estrella
AU - Cruz-Irisson, Miguel
N1 - Funding Information:
This work was partially supported by the multidisciplinary project 2012–1439 from SIP-Instituto Politécnico Nacional, PICSO12-085 from Instituto de Ciencia y Tecnología del Distrito Federal (ICyTDF) and IB101712-2 from PAPIIT-UNAM.
PY - 2012
Y1 - 2012
N2 - A computational study of the dependence of the electronic band structure and density of states on the chemical surface passivation of cubic porous silicon carbide (pSiC) was performed using ab initio density functional theory and the supercell method. The effects of the porosity and the surface chemistry composition on the energetic stability of pSiC were also investigated. The porous structures were modeled by removing atoms in the [001] direction to produce two different surface chemistries: one fully composed of silicon atoms and one composed of only carbon atoms. The changes in the electronic states of the porous structures as a function of the oxygen content at the surface were studied. Specifically, the oxygen content was increased by replacing pairs of H atoms on the pore surface with oxygen (O) atoms attached to the surface via either a double bond (X = O) or a bridge bond (X-O-X, X = Si or C). The calculations show that for the fully H-passivated surfaces, the forbidden energy band is larger for the C-rich phase than for the Si-rich phase. For the partially oxygenated Si-rich surfaces, the band gap behavior depends on the O bond type. The energy gap increases as the number of O atoms increases in the supercell if the O atoms are bridgebonded, whereas the band gap energy does not exhibit a clear trend if O is double-bonded to the surface. In all cases, the gradual oxygenation decreases the band gap of the C-rich surface due to the presence of trap-like states.
AB - A computational study of the dependence of the electronic band structure and density of states on the chemical surface passivation of cubic porous silicon carbide (pSiC) was performed using ab initio density functional theory and the supercell method. The effects of the porosity and the surface chemistry composition on the energetic stability of pSiC were also investigated. The porous structures were modeled by removing atoms in the [001] direction to produce two different surface chemistries: one fully composed of silicon atoms and one composed of only carbon atoms. The changes in the electronic states of the porous structures as a function of the oxygen content at the surface were studied. Specifically, the oxygen content was increased by replacing pairs of H atoms on the pore surface with oxygen (O) atoms attached to the surface via either a double bond (X = O) or a bridge bond (X-O-X, X = Si or C). The calculations show that for the fully H-passivated surfaces, the forbidden energy band is larger for the C-rich phase than for the Si-rich phase. For the partially oxygenated Si-rich surfaces, the band gap behavior depends on the O bond type. The energy gap increases as the number of O atoms increases in the supercell if the O atoms are bridgebonded, whereas the band gap energy does not exhibit a clear trend if O is double-bonded to the surface. In all cases, the gradual oxygenation decreases the band gap of the C-rich surface due to the presence of trap-like states.
KW - DFT
KW - Electronic properties
KW - Oxygenation
KW - Porous nanostructures
KW - Porous silicon carbide
KW - Surface passivation
UR - http://www.scopus.com/inward/record.url?scp=84866117306&partnerID=8YFLogxK
U2 - 10.1186/1556-276X-7-471
DO - 10.1186/1556-276X-7-471
M3 - Artículo
C2 - 22913486
SN - 1931-7573
VL - 7
JO - Nanoscale Research Letters
JF - Nanoscale Research Letters
M1 - 471
ER -