| Autor: |
Li C; Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States., Oliveira EF; School of Sciences, Department of Physics and Meteorology, São Paulo State University (Unesp), Bauru, São Paulo 17033-360, Brazil., Biswas A; Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States., Puthirath AB; Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States., Zhang X; Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States., Pramanik A; Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States., Garratt EJ; DEVCOM Army Research Laboratory, Adelphi, Maryland 20783, United States., Neupane MR; DEVCOM Army Research Laboratory, Adelphi, Maryland 20783, United States., Pate BB; Chemistry Division, Naval Research Laboratory, Washington, D.C. 20375, United States., Birdwell AG; DEVCOM Army Research Laboratory, Adelphi, Maryland 20783, United States., Ivanov TG; DEVCOM Army Research Laboratory, Adelphi, Maryland 20783, United States., Terlier T; Shared Equipment Authority, Rice University, Houston, Texas 77005, United States., Vajtai R; Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States., Ajayan PM; Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States. |
| Abstrakt: |
Diamond surface functionalization has received significant research interest recently. Specifically, H-termination has been widely adopted because it endows the diamond surface with negative electron affinity and the hole carrier is injected in the presence of surface transfer dopants. Exploring different functional groups' attachment on diamond surfaces and their impact on the electronic structure, using wet and dry chemical approaches, would hence be of interest in engineering diamond as a semiconductor. Here, we report the functionalization of the H-terminated diamond surface with nitrogen and sulfur heteroatoms. Surface characterization of functionalized diamond surfaces shows that these groups are well-distributed and covalently bonded to diamonds. Four chemical functional groups (-SH, -S-S-, -S-O, and -S=O) were found on the sulfurized diamond surface, and two groups (-NH 2 and =NH) upon amination. We also report co-functionalization of surface with N and S (N-S), where sulfurization promotes sequential amination efficiency with reduced exposure time. Electrical measurement shows that heteroatom-modified diamond surfaces possess higher conductivity than H-terminated diamonds. Density functional theory (DFT) shows that upon functionalization with various N/S ratios, the conduction band minimum and valence band maximum downshift, which lowers the bandgap in comparison to an H-terminated diamond. These observations suggest the possibility of heteroatom functionalizations with enhanced surface electrical conductivity on the diamond that are useful for various electronic applications. |
