Facile assembly of SnO2 thin film-based Al/SnO2/Al device for sensing of 260 nm UVC and 365 nm UVA radiation

• Published in: Sensors and actuators. A. Physical. Vol. 379; p. 115991
• Main Authors: Koushik, Ronald P., Kalita, J.M., Mishra, Rajan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2024
• Subjects: Photoresponsivity; Response time; SnO2; Thin film; UVC and UVA sensor; UVC and UVA sensor; SnO2; Response time; Photoresponsivity; Thin film
• ISSN: 0924-4247
• DOI: 10.1016/j.sna.2024.115991

An Al/SnO2/Al metal-semiconductor-metal (MSM) device was formed by depositing a ∼55 nm thin film of SnO2 on Si substrate. Structural, surface morphology and optical properties of the SnO2 film were studied. The current-voltage (I-V) characteristics of the device were recorded under the dark condition followed by 260 nm-UVC and 365 nm-UVA illumination conditions. Under the dark condition, the device shows a resistivity of 8.05 Ωcm at V=1.5 V bias voltage. The device produces nearly symmetric rectifying-type I-V characteristics under forward and reverse bias conditions. The electrical properties of the device were explained using back-to-back Schottky diode model. Under the dark condition, the ideality factor of the junction under forward and reverse bias were estimated to be 1.08 and 1.72 respectively. The external quantum efficiency of the device under UVC was found to be ∼518.72 % and specific detectivity reached as high as 1.03×109 Jones at 2.0 V with a response time of ∼1 s. The device showed a high signal-to-noise ratio between 0.5 and 1.5 V bias voltages. The values of the ideality factor being greater than 1 was attributed to the presence of point defects in the SnO2 layer as verified by photoluminescence study. This study reveals that the device could be used as a UVC and UVA sensor at a relatively low bias voltage of ∼1.5 V. [Display omitted] •Metal-semiconductor-metal device was formed using a 55 nm SnO2 thin film.•260 nm UVC and 365 nm UVA radiation sensing properties of the device were studied.•Current conduction through the device follows back-to-back Schottky diode model.•The specific detectivity of the device was found to be 1.028×109 Jones at 2.0 V.•The quantum efficiency was found to be 518.72 % for UVC radiation.