Two-Dimensional Bi<sub>2</sub>O<sub>5</sub>Te Nanosheets for Sensitive and Fast Response Broadband Visible Light Photodetectors
Prabhukrupa Chinmay Kumar, Gopal K. Pradhan, Subrata Senapati, Ramakanta Naik
Abstract
2D materials showcase numerous distinct optical and electronic characteristics that are incredibly essential for implementation in optoelectronic devices. In the past few years, photodetectors have been a significant focus because of their diverse applications. The challenge lies in developing environmentally friendly materials to fabricate cost-effective, high-performance devices. Bismuth oxychalcogenide nanosheets (Bi 2 O 2 X, X = S, Se, Te) in their 2D form, due to their impressive theoretical and experimental characteristics, have become promising alternatives for potential applications in optoelectronic devices. One of its most common oxide phases, i.e., Bi 2 O 5 Te, also possesses quite interesting nonlinear optical, photorefractive, and many other physical properties, which have yet to be explored. Here, this study reports the photodetectors based on 2D Bi 2 O 5 Te nanomaterials prepared using a “microwave-assisted method,” an exciting choice for synthesizing such nanomaterials in bulk. The basic characterizations confirmed the sample’s phase and presence of constituent elements, whereas microscopic studies demonstrated its 2D layered nature. Verification of different bonds between the atoms is observed in the Raman studies. Optical studies represent the band edges of the samples between 400 to 600 nm, which is significant as it is useful in optoelectronic devices such as solar cells, LEDs, and photodetectors. The band gaps of the materials appeared to be in the 2.72 to 2.95 eV range. Centers of the broad photoluminescence spectra are obtained around 650–700 nm, which suggests the optoelectronics applicability of the material. Figures of merits such as sensitivity, responsivity, and detectivity values are obtained from the photodetection measurements. Time-dependent photoresponse characteristics show a high I on / I off ratio, which is quite impressive for fabricating highly sensitive photodetectors.