Nanostructured hydrogenated amorphous carbon films doped with nitrogen on p-silicon

• Published in: Physica status solidi. A, Applications and materials science Vol. 203; no. 8; pp. 1982 - 1991
• Main Authors: Somani, Prakash R., Yoshida, Akihiko, Afre, Rakesh A., Adhikary, Sunil, Soga, T., Umeno, M.
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01.06.2006; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: 61.72.Cc; 61.72.Ff; 61.72.Yx; 81.05.Cy; 81.40.Ef; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in multilayers, nanoscale materials and structures; Exact sciences and technology; Materials science; Nanoscale materials and structures: fabrication and characterization; Other topics in nanoscale materials and structures; Physics; Scanning electron microscopy; Particle size; Electrical conductivity; Microwave radiation; Doping; Nanostructures; Carbon; Energy gap; Surface waves; Impurities; Amorphous hydrogenated material; Nitrogen additions; Donor center; PECVD; Depth profiles; X-ray photoelectron spectra
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.200522116

The synthesis of nanostructured hydrogenated amorphous carbon (a‐C:H) films doped with nitrogen using microwave‐assisted surface wave plasma chemical vapour deposition on quartz and p‐silicon substrates is reported. By controlling the deposition parameters, the Tauc band gap has been varied from 2.4 to 1.75 eV. Field emission scanning electron microscopy observations indicate that the films are nano‐ structured and the particle size varies considerably depending on the deposition conditions. Nitrogen seems to be responsible for the formation of the nanostructure. X‐ray photoelectron spectroscopy studies with depth profiling indicate that nitrogen is not uniformly distributed in the bulk of the films and the films are observed to be rich in carbon near the p‐silicon substrate. Nitrogen concentration increases away from the substrate towards the top surface. Resistivity, visible Raman and nitrogen/carbon ratio studies indicate that a significant amount of sp3 carbon is present in the films and nitrogen seems to be a weak donor in the a‐C:H matrix. Weak photovoltaic action is observed in nitrogen‐doped a‐C:H/p‐silicon cells. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)