Effects of iodine doping on optoelectronic properties of diamond-like carbon thin films deposited by microwave surface wave plasma CVD

• Published in: Diamond and related materials Vol. 13; no. 11; pp. 2136 - 2139
• Main Authors: Omer, Ashraf M.M., Adhikari, Sudip, Adhikary, Sunil, Uchida, Hideo, Umeno, Masayoshi
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2004; Elsevier
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Diamond-like carbon; Exact sciences and technology; Iodine doping; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Microwave surface wave plasma CVD; Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity); Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Optoelectronic properties; Physics; Iodine doping; Diamond-like carbon; Optoelectronic properties; Microwave surface wave plasma CVD; Photovoltaic effects; Inorganic compounds; Doping; Experimental study; Carbon; Absorption coefficients; Thin films; CVD; Growth from vapor; Diamond lattices; Surface waves; Iodine additions; Preparation; Photoconductivity; IV characteristic; Current density; Microwave discharge
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2004.05.010

We report the effects of iodine (I) doping on the electrical and optical properties of diamond-like carbon (DLC) thin films grown on silicon and quartz substrates by microwave surface wave plasma chemical vapor deposition at low temperature (<100 °C). For film deposition, we used argon gas with methane or camphor dissolved with ethyl alcohol composition as plasma source. The optical gap and photoconductivity measurements of the samples were carried out before and after the iodine doping. The results show that optical gap dropped from 3.4 to 0.9 eV corresponding to nondoping to iodine-doping conditions, respectively. The photovoltaic measurements show that the open-circuit voltage ( V oc) and short-circuit current density ( J sc) of I-doped DLC film deposited on n-type silicon substrate under light illumination (AM1.5, 100 mW/cm 2) were approximately 177 mV and 1.15 μA, respectively, and the fill factor was found to be 0.217.