Print Email Facebook Twitter The effect of boron concentration on the electrical, morphological and optical properties of boron-doped nanocrystalline diamond sheets Title The effect of boron concentration on the electrical, morphological and optical properties of boron-doped nanocrystalline diamond sheets: Tuning the diamond-on-graphene vertical junction Author Rycewicz, M.K. (TU Delft Micro and Nano Engineering; Gdansk University of Technology) Nosek, Adrian (University of California) Shin, D. (TU Delft QN/Steeneken Lab; Kavli institute of nanoscience Delft) Ficek, Mateusz (Gdansk University of Technology) Buijnsters, J.G. (TU Delft Micro and Nano Engineering) Bogdanowicz, Robert (Politechnika Gdanska) Date 2022 Abstract In this paper, the effect of boron doping on the electrical, morphological and structural properties of free-standing nanocrystalline diamond sheets (thickness ~ 1 μm) was investigated. For this purpose, we used diamond films delaminated from a mirror-polished tantalum substrate following a microwave plasma-assisted chemical vapor deposition process, each grown with a different [B]/[C] ratio (up to 20,000 ppm) in the gas phase. The developed boron-doped diamond (BDD) films are a promising semiconducting material for sensing and high-power electronic devices due to band gap engineering and thermal management feasibility. The increased boron concentration in the gas phase induces a decrease in the average grain size, consequently resulting in lower surface roughness. The BDD sheets grown with [B]/[C] of 20,000 ppm reveal the metallic conductivity while the lower doped samples show p-type semiconductor character. The charge transport at room temperature is dominated by the thermally activated nearest-neighbor hopping between boron acceptors through impurity band conduction. At low temperatures (<300 K), the Arrhenius plot shows a non-linear temperature dependence of the logarithmic conductance pointing towards a crossover towards variable range hopping. The activation energy at high temperatures obtained for lowly-doped sheets is smaller than for nanocrystalline diamond bonded to silicon, while for highly-doped material it is similar. Developed sheets were utilized to fabricate two types of diamond-on-graphene heterojunctions, where boron doping is the key factor for tuning the shape of the current-voltage characteristics. The graphene heterojunction with the low boron concentration diamond sheet resembles a Schottky junction behavior, while an almost Ohmic contact response is recorded with the highly doped BDD sheet of metallic conductivity. The free-standing diamond sheets allow for integration with temperature-sensitive interfaces (i.e. 2D materials or polymers) and pave the way towards flexible electronics devices. Subject Boron-doped diamond (BDD)Electrical conductivityGrapheneHeterojunctionNanocrystalline sheets To reference this document use: http://resolver.tudelft.nl/uuid:f912aeef-af94-4c32-890b-6917bb48f6a9 DOI https://doi.org/10.1016/j.diamond.2022.109225 ISSN 0925-9635 Source Diamond and Related Materials, 128 Part of collection Institutional Repository Document type journal article Rights © 2022 M.K. Rycewicz, Adrian Nosek, D. Shin, Mateusz Ficek, J.G. Buijnsters, Robert Bogdanowicz Files PDF 1_s2.0_S0925963522004071_main.pdf 1.97 MB Close viewer /islandora/object/uuid:f912aeef-af94-4c32-890b-6917bb48f6a9/datastream/OBJ/view