Disentangling the Role of the SnO Layer on the Pyro‐Phototronic Effect in ZnO‐Based Self‐Powered Photodetectors

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 19; no. 32; pp. e2300607 - n/a
• Main Authors: Vieira, Eliana M. F., Silva, José P. B., Gwozdz, Katarzyna, Kaim, Adrian, Gomes, Nuno M., Chahboun, Adil, Gomes, Maria J. M., Correia, José H.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01-08-2023
• Subjects: Aluminum; Electric fields; Nanotechnology; n‐p‐n heterojunction; Optoelectronic devices; Photoelectric effect; Photometers; Photovoltaic cells; pyro‐phototronic effect; self‐powered photodetectors; Silicon substrates; ultrafast photosensors; Zinc oxide; pyro-phototronic effect; ultrafast photosensors; self-powered photodetectors; n-p-n heterojunction
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202300607

Self‐powered photodetectors (PDs) have been recognized as one of the developing trends of next‐generation optoelectronic devices. Herein, it is shown that by introducing a thin layer of SnO film between the Si substrate and the ZnO film, the self‐powered photodetector Al/Si/SnO/ZnO/ITO exhibits a stable and uniform violet sensing ability with high photoresponsivity and fast response. The SnO layer introduces a built‐in electrostatic field to highly enhance the photocurrent by over 1000%. By analyzing energy diagrams of the p‐n junction, the underlying physical mechanism of the self‐powered violet PDs is carefully illustrated. A high photo‐responsivity (R) of 93 mA W−1 accompanied by a detectivity (D*) of 3.1 × 1010 Jones are observed under self‐driven conditions, when the device is exposed to 405 nm excitation laser wavelength, with a laser power density of 36 mW cm−2 and at a chopper frequency of 400 Hz. The Si/SnO/ZnO/ITO device shows an enhancement of 3067% in responsivity when compared to the Al/Si/ZnO/ITO. The photodetector holds an ultra‐fast response of ≈ 2 µs, which is among the best self‐powered photodetectors reported in the literature based on ZnO.
Self‐powered ZnO‐based photodetector with an optimum responsivity (R) and detectivity (D*)of 93 mA W−1 and 3.1 × 1010 Jones, respectively, for a laser power density of 36 mW cm−2 and a chopper frequency of 400 Hz. The SnO layer introduces a built‐in electrostatic field to highly enhance the photocurrent by over 1000%. Ultrafast rise and fall times of 2.2 and 2.0 µs, respectively, were obtained.