TY - JOUR
T1 - Characterization of Surface and Structure of In Situ Doped Sol-Gel-Derived Silicon Carbide
AU - Kettner, Olivia
AU - Šimić, Sanja
AU - Kunert, Birgit
AU - Schennach, Robert
AU - Resel, Roland
AU - Grießer, Thomas
AU - Friedel, Bettina
PY - 2018
Y1 - 2018
N2 - Silicon carbide (SiC), is an artificial semiconductor used for high-power transistors and blue LEDs, for its extraordinary properties. SiC will be attractive for more applications, but large-scale or large-surface area fabrication, with control over defects and surface is challenging. Sol-gel based techniques are an affordable alternative toward such requirements. This report describes two types of microcrystalline SiC derived after carbothermal reduction from sol-gel-based precursors, one with nitrogen added, the other aluminum. Characterization of their bulk, structure, and surface shows that incorporation of dopants affects the formation of polytypes and surface chemistry. Nitrogen leads exclusively to cubic SiC, exhibiting a native oxide surface. Presence of aluminum instead promotes growth of hexagonal polytypes and induces self-passivation of the crystallites' surface during growth. This is established by hydrogenation of silicon bonds and formation of a protecting aluminum carbonate species. XPS provides support for the suggested mechanism. This passivation is achieved in only one step, solely by aluminum in the precursor. Hence, it is shown that growth, doping and passivation of SiC can be performed as "one-pot synthesis". Material without insulating oxide and a limited number of defects is highly valuable for applications involving surface-sensitive charge-transfer reactions, therefore the potential of this method is significant.
AB - Silicon carbide (SiC), is an artificial semiconductor used for high-power transistors and blue LEDs, for its extraordinary properties. SiC will be attractive for more applications, but large-scale or large-surface area fabrication, with control over defects and surface is challenging. Sol-gel based techniques are an affordable alternative toward such requirements. This report describes two types of microcrystalline SiC derived after carbothermal reduction from sol-gel-based precursors, one with nitrogen added, the other aluminum. Characterization of their bulk, structure, and surface shows that incorporation of dopants affects the formation of polytypes and surface chemistry. Nitrogen leads exclusively to cubic SiC, exhibiting a native oxide surface. Presence of aluminum instead promotes growth of hexagonal polytypes and induces self-passivation of the crystallites' surface during growth. This is established by hydrogenation of silicon bonds and formation of a protecting aluminum carbonate species. XPS provides support for the suggested mechanism. This passivation is achieved in only one step, solely by aluminum in the precursor. Hence, it is shown that growth, doping and passivation of SiC can be performed as "one-pot synthesis". Material without insulating oxide and a limited number of defects is highly valuable for applications involving surface-sensitive charge-transfer reactions, therefore the potential of this method is significant.
KW - Self-passivation
KW - Silicon carbide
KW - Sol-gel processing
KW - Surface termination
UR - http://www.scopus.com/inward/record.url?scp=85042465639&partnerID=8YFLogxK
U2 - 10.1002/adem.201701067
DO - 10.1002/adem.201701067
M3 - Article
AN - SCOPUS:85042465639
SN - 1438-1656
VL - 20
SP - 1
EP - 9
JO - Advanced Engineering Materials
JF - Advanced Engineering Materials
M1 - 1701067
ER -