Patterned carbon dot-based thin films for solid-state devices

• Published in: Nanoscale 2020-05, Vol.12 (18), p.1254-1264
• Main Authors: Segkos, Apostolos, Sakellis, Ilias, Boukos, Nikolaos, Drivas, Charalampos, Kennou, Stella, Kordatos, Konstantinos, Tsamis, Christos
• Format: Article
• Language: English
• Subjects: Carbon; Carbon dots; Citric acid; Fluorescence; Functional groups; Heat treatment; Nanocomposites; Optical properties; Patterning; Plasma etching; Quantum dots; Relative humidity; Silicon dioxide; Solid state devices; Substrates; Thin films
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c9nr08904g

Carbon dot-based fluorescent nanocomposite compounds were obtained following microwave assisted thermal treatment of an aqueous mixture consisting of citric acid and urea. Thin film deposition of nanocomposites on SiO 2 (100) substrates is followed by annealing, in order to render the films dissolution-resistant and processable. Optical lithography and O 2 plasma etching are utilized to pattern the deposited films in the desired shapes and dimensions and a solid-state relative humidity sensor is fabricated on the SiO 2 substrate. Spectroscopy and microscopy techniques are employed to characterize and monitor the whole process throughout the fabrication steps. The patterned films retain the functional groups introduced during their synthesis and continue to display hydrophilicity and PL properties. Successful patterning of these nanocomposites opens the way for the fabrication of solid-state, carbon dot-based optical and electrical devices that take advantage of the properties of carbon quantum dots. We report a methodology for the deposition and further manipulation of fluorescent CQD-based nanocomposite thin films on SiO 2 substrates, to obtain dissolution resistant, lithographically patterned films that retain their fluorescent properties.