Investigation of the electrical properties of electrochemically grown DLC films doped with specific elements (S, N, Cu) in Schottky structures as interlayers

This study examines the electrical and photoelectrical properties of diamond-like carbon (DLC) films, both undoped and doped with specific elements (S, N, Cu), deposited on p-Si grown by the electrochemical method. One of the key benefits of this method is its cost-effectiveness, as they do not require the use of high temperatures or vacuum systems. Herein, the experimental procedures are carried out at low voltages and room temperature. The current-voltage (I-V) and impedance-voltage (Z-V) characteristics of the four Schottky-type structures interlaid with undoped and doped-DLC (S/N/Cu-doped DLC) were probed and explained how doping affects the basic diode parameters and, consequently, the device performance. The surface state distributions (Nss) are examined through both characteristics. Moreover, the impact of illumination on photocapacitance and photoconductance is investigated under 100 mW.cm−2. The presence of photoexcited charge carriers and/or trapped charges resulted in significant changes to both capacitance and conductance values. It was noted that there was a reduction in conductance values under illumination in S and N-doped DLC interlayer structures. This phenomenon is known as negative photoconductance, which is thought to be caused by trapped charges, as discussed in the literature. It was observed that doping DLC with certain elements resulted in alterations to the electrical properties of the structures, as discussed by changes to the Nss distributions and bond characteristics under illumination and electric field. •Undoped and doped DLC films were grown using the electrochemical method.•Diode characteristics and parameters of DLC film interlaid Schottky structures are discussed.•Capacitance and conductance changes were investigated both as a function of voltage and illumination.•Trapping-associated negative photoconductance behaviors were observed in S- and N-doped DLC interlaid structures.