Low temperature synthesis of transparent conductive boron doped diamond films for optoelectronic applications: Role of hydrogen on the electrical properties

Transparent conductive electrodes are principal components in various optoelectronic devices and technologies. As such, diamond coatings in the form of electrically conductive thin films are envisioned to provide advantageous chemical and mechanical characteristics/stability in a variety of modern technologies including optoelectronics, biosensing, electrochemical and micromechanical systems. However, deposition of electrically conductive polycrystalline diamond coatings for such applications is currently a challenging task, since temperatures above 600 degrees C are usually required to ensure good diamond layer quality, which in turn limits the selection of substrates, to materials capable of withstanding exposure to high temperatures. In the present work, we investigate routes toward enhancement of electrical characteristics of nanocrystalline boron-doped diamond (BDD) films fabricated at low temperatures via chemical vapour deposition. We found that post-growth processing of BDD layers enhances their electrical properties, which otherwise are dependent on the employed deposition temperature regime. Finally, we show that integration of an electrically conductive Ti grid opens a route for fabrication of highly transparent and conductive composite nanocrystalline BDD electrodes over large areas at temperatures as low as 250 degrees C. (C) 2020 Elsevier Ltd. All rights reserved.