Electrical Behavior of Hydrogen-Induced Ultra Nano-Crystalline Diamond
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2025-05-08 |
| Journal | Current Nanomaterials |
| Authors | Ramakgahlela Wendy Thoka, S.J. Moloi, Dilip Kumar Mishra, Sekhar C. Ray |
| Institutions | University of South Africa, Siksha O Anusandhan University |
Abstract
Section titled āAbstractāBackground: Ultra-nanocrystalline diamond (UNCD) films, in the context of semiconduc-tor and optoelectronic devices, represent a promising avenue for developing highly versatile and effi-cient technologies, leveraging their unique properties for versatile applications. Objective: The development of the unique morphology of UNCD films that could be used in versatile semiconductor/optoelectronics devices. Methods: In this study, a microwave plasma-enhanced chemical vapor deposition process was used to grow the UNCD thin films on silicon (100) substrates. The process was performed under various gas composition plasma atmospheres (H2, N2, Ar, and CH4) at a pressure of 120 Torr and the substrate temperature of 700Ā°C after the creation of nano-sized diamond powder nucleation sites with a seeding density of ā2 Ć 1012 cmā2. Scanning electron microscopy images and x-ray diffraction techniques were used to study the surface morphology and crystal structure. For the Raman spectroscopy tech-nique, four different excitation wavelengths of LASER light (448, 515, 647, 785 nm) were used to confirm the formation of higher sp3-content, grain boundaries, structural diamond phase, and their dispersive/non-dispersive spectral components. C1s, O 1s, and N 1s X-ray photoelectron spectroscopy technique was employed to study the electronic/bonding structure of UNCD thin films, whereas ultra-violet (UV) photoemission technique was used to determine the work functions () and valence band maximum (VBM) of the UNCD films. Results: It was observed that the nano-structured UNCD film was dependent on the sp3-content pres-ence in the film structure along with sp3-content and grain boundaries. The lowest and VBM were obtained when the H2 introduction was 8 sccm and 5 sccm, respectively. Electron field emission re-sults showed that the turn-on electric field (E0) is increased with an increase in the introduction of H2 flow rate during the preparation of UNCD films, resulting in an increase in the sp3-content in the film structure. The current-voltage (I-V) characteristics indicated that the conductivity of the films was low, with a current of ~10-10 A. Conclusion: The prepared UNCD films were found suitable for the fabrication of transient testing, memristors, and other versatile semiconductor/optoelectronics devices.