Structural and optoelectronic characterization of Cu2CoSnS4 quaternary functional photodetectors

• Published in: Optik (Stuttgart) 2020-06, Vol.212, p.164724, Article 164724
• Main Authors: İlhan, Mustafa, Koç, Mümin Mehmet, Coşkun, Burhan, Dere, Ayşegül, Yakuphanoğlu, Fahrettin
• Format: Article
• Language: English
• Subjects: Cu2NiSnS4photodiodes; Photodetector; Photoresponse; Quaternary functional photodiodes; Solar detectors
• ISSN: 0030-4026; 1618-1336
• DOI: 10.1016/j.ijleo.2020.164724

Al/p-Si/Cu2CoSnS4/Al quaternary functional semiconductor photodetectors showing solar detector properties were produced via sol-gel method. SEM, EDS and XRD techniques were used in the confirmation of the chemical composition of the photodiodes where nanoparticle like characteristics of Cu2CoSnS4 was seen. UV–vis spectroscopy was used in the investigation of optoelectronic characteristics. It was seen that photodiodes have a high absorption rate with minimum reflectance, bandgap energy was calculated as 1.19 eV. Current – time and current – voltage characteristics of the photodiodes revealed that photodiodes are sensitive to daylight; photodiodes present rectifying characteristics. Thermionic emission theory was used in the calculation of barrier height, ideality factor, photoresponse, photosensitivity, and linear dynamic rate characteristics. Capacitance – voltage, conductance – voltage, corrective capacitance – voltage, corrective conductance – voltage graphs were used to investigate the electrical properties of the Al/p-Si/Cu2CoSnS4/Al photodiodes. The electrical characteristics of the photodiodes reflect frequency dependent characteristics. Such a behaviour was found to be an indication of the existence of interface states. The density of interface (Dit) calculations revealed that the density of interface states strongly depends on AC signal frequency where diminished Dit was seen for increased signal frequency.