Investigation of optoelectrical and Schottky behavior of diamond-like carbon coating deposited by hollow cathode PACVD method

Abstract

In the present study, diamond-like carbon (DLC) was deposited on a silicon substrate by hollow cathode plasma-assisted chemical vapor deposition (PACVD) method. After deposition, structural, optical and, electrical properties of DLC were investigated. The Raman spectroscopy proved that DLC layer successfully formed on the substrate. Scanning electron microscopy images showed that the DLC had a smooth and uniform surface with a thickness of about 392 nm. Energy-dispersive X-ray analysis demonstrated the presence of carbon as the main constituent of DLC in the formed layer. The optical properties of DLC were investigated by UV–Vis and photoluminescence spectroscopy. The absorption peak for the DLC was at 370 nm. Based on the results of UV–Vis spectroscopy, a tauc plot was calculated, and it was found that the DLC has a band gap of 2.37 eV. The PL spectra also showed that the DLC layer would emit at 410 nm if adequately excited. Also, the current-voltage characteristic for the Au/DLC/p-Si was measured. Based on the current-voltage results, the sensitivity parameter was calculated, which was equal to 9.71. Finally, based on the measured values, the feasibility of using the DLC layer as a semiconductor for use in Schottky junctions was investigated. • A uniform layer of DLC was deposited on a silicon substrate by hollow cathode PACVD method. •It was found that the DLC layer has a bandgap of 2.37 eV and the absorption peak located at 370 nm, which makes this material suitable for use as a detector in this range. •The gold electrodes were placed on the DLC by a sputtering method to form an Au/DLC/p-Si arrangement as a Schottky junction. •The electrical characterization of the Au/DLC/p-Si device was measured, and its basic parameters calculated, and finally, the possibility of using DLC as a semiconductor in the Schottky junction was investigated.