Ultrahigh Infrared Photoresponse from Core–Shell Single‐Domain‐VO₂/V₂O₅ Heterostructure in Nanobeam

Abstract

Infrared (IR) harvesting and detection in red and near‐IR (NIR) part of the solar spectrum have always been a long‐term research area of intense interest. However, limited choices of current photoactive materials have significantly hampered the realization of ultrahigh IR sensitivity under room temperature conditions. The trigger for this requires the exploration of new photo­active materials and the ability to fabricate new photoactive structural design. Herein, a new oxide‐catalogue photoconductive NIR detector with ultrahigh performance built by core/shell nanobeam heterostructures (CSNHs) with the inner single‐domain monoclinic VO 2 (M) core and outer V 2 O 5 shell, which is the first example of photoconductive IR detector made from transition metal oxides (TMOs), is presented. Benefited from the well‐defined TMO hetero­junction interface, the ultrahigh responsivity ( R λ ) of 2873.7 A W ‐1 and specific detectivity (D*) of 9.23 × 10 12 Jones are achieved at room temperature (at 990 nm; 0.2 mW cm ‐2 ), recording the best performance compared with those reported IR detectors based on heavy‐metal‐free materials, and even comparable/superior to those traditional ones made from materials including heavy metals. These findings pave a new way to design oxide heterostructures for intriguing applications in optoelectronic and energy harvesting nanodevices.