Abstract The chemical nature of sub-monolayer phosphorous impurities at the SiC/SiO2 interface is... more Abstract The chemical nature of sub-monolayer phosphorous impurities at the SiC/SiO2 interface is a critical surface science problem related to device performance and other applications. In this study, SiO2 films containing phosphorus were deposited by sputtering on both the Si and C-faces of SiC substrates, and on silicon (Si(100)) substrates. After oxide removal by etching, a significant amount of phosphorus was retained on both SiC surfaces, while no phosphorus was observed on the Si surface. Chemical ambient investigation, quantification by XPS, and water contact angle measurements indicate that the phosphorus on the SiC surface is trivalent bonded, mainly to oxygen. Based on these results, a SiO2/SiC interfacial structure is proposed: Si-C-Si-|-O-P-O2-SiO2. These results provide new insights into the role of phosphorus, its incorporation, and stability, as a passivating agent in the performance of SiC MOS structures.
Graphene is a breakthrough 2D material due to its unique mechanical, electrical, and thermal prop... more Graphene is a breakthrough 2D material due to its unique mechanical, electrical, and thermal properties, with considerable responsiveness in real applications. However, the coverage of large areas with pristine graphene is a challenge and graphene derivatives have been alternatively exploited to produce hybrid and composite materials that allow for new developments, considering also the handling of large areas using distinct methodologies. For electronic applications it is highly keen the investigation of electrical properties of graphene derivatives and related composites to determine whether the characteristic 2D charge transport of pristine graphene is preserved. Here, we report a systematic study of the charge transport mechanisms of reduced graphene oxide (rGO) chemically functionalized with sodium polystyrene sulfonate (PSS), named as GPSS. GPSS was produced either as quantum dots (QDs) or nanoplatelets (NPLs), being further nanostructured with poly(diallyldimethylammonium chl...
Fabrication and testing of micro-reactors for the characterization of nanosensors is presented in... more Fabrication and testing of micro-reactors for the characterization of nanosensors is presented in this work. The reactors have a small volume (100 μl) and are equipped with gas input/output channels. They were machined from a single piece of kovar in order to avoid leaks in the system due to additional welding. The contact pins were electrically insulated from the body of the reactor using a borosilicate sealing glass and the reactor was hermetically sealed using a lid and an elastomeric o-ring. One of the advantages of the reactor lies in its simple assembly and ease of use with any vacuum/gas system, allowing the connection of more than one device. Moreover, the lid can be modified in order to fit a window for in situ optical characterization. In order to prove its versatility, carbon nanotube-based sensors were tested using this micro-reactor. The devices were fabricated by depositing carbon nanotubes over 1 μm thick gold electrodes patterned onto Si/SiO2 substrates. The sensors ...
Abstract The influence of a substrate D.C. polarization on the doping efficiency in a-Si:H is rep... more Abstract The influence of a substrate D.C. polarization on the doping efficiency in a-Si:H is reported. Intrinsic layers of solar cells and n-i-n structures were also grown under different substrate polarizations and their influence on i-layer properties is discussed.
Abstract The chemical nature of sub-monolayer phosphorous impurities at the SiC/SiO2 interface is... more Abstract The chemical nature of sub-monolayer phosphorous impurities at the SiC/SiO2 interface is a critical surface science problem related to device performance and other applications. In this study, SiO2 films containing phosphorus were deposited by sputtering on both the Si and C-faces of SiC substrates, and on silicon (Si(100)) substrates. After oxide removal by etching, a significant amount of phosphorus was retained on both SiC surfaces, while no phosphorus was observed on the Si surface. Chemical ambient investigation, quantification by XPS, and water contact angle measurements indicate that the phosphorus on the SiC surface is trivalent bonded, mainly to oxygen. Based on these results, a SiO2/SiC interfacial structure is proposed: Si-C-Si-|-O-P-O2-SiO2. These results provide new insights into the role of phosphorus, its incorporation, and stability, as a passivating agent in the performance of SiC MOS structures.
Graphene is a breakthrough 2D material due to its unique mechanical, electrical, and thermal prop... more Graphene is a breakthrough 2D material due to its unique mechanical, electrical, and thermal properties, with considerable responsiveness in real applications. However, the coverage of large areas with pristine graphene is a challenge and graphene derivatives have been alternatively exploited to produce hybrid and composite materials that allow for new developments, considering also the handling of large areas using distinct methodologies. For electronic applications it is highly keen the investigation of electrical properties of graphene derivatives and related composites to determine whether the characteristic 2D charge transport of pristine graphene is preserved. Here, we report a systematic study of the charge transport mechanisms of reduced graphene oxide (rGO) chemically functionalized with sodium polystyrene sulfonate (PSS), named as GPSS. GPSS was produced either as quantum dots (QDs) or nanoplatelets (NPLs), being further nanostructured with poly(diallyldimethylammonium chl...
Fabrication and testing of micro-reactors for the characterization of nanosensors is presented in... more Fabrication and testing of micro-reactors for the characterization of nanosensors is presented in this work. The reactors have a small volume (100 μl) and are equipped with gas input/output channels. They were machined from a single piece of kovar in order to avoid leaks in the system due to additional welding. The contact pins were electrically insulated from the body of the reactor using a borosilicate sealing glass and the reactor was hermetically sealed using a lid and an elastomeric o-ring. One of the advantages of the reactor lies in its simple assembly and ease of use with any vacuum/gas system, allowing the connection of more than one device. Moreover, the lid can be modified in order to fit a window for in situ optical characterization. In order to prove its versatility, carbon nanotube-based sensors were tested using this micro-reactor. The devices were fabricated by depositing carbon nanotubes over 1 μm thick gold electrodes patterned onto Si/SiO2 substrates. The sensors ...
Abstract The influence of a substrate D.C. polarization on the doping efficiency in a-Si:H is rep... more Abstract The influence of a substrate D.C. polarization on the doping efficiency in a-Si:H is reported. Intrinsic layers of solar cells and n-i-n structures were also grown under different substrate polarizations and their influence on i-layer properties is discussed.
Uploads
Papers by Angelo Gobbi