Photothermal‐Induced Electrical Behavior of Micron‐Sized Platinum Structures and Their Efficient Photodetection

Abstract

Photothermal effects have recently been widely investigated for applications in the fields of biomedicine, physics, and chemistry. Unfortunately, only a few reports describe their potential use in ultrafast photodetectors. Herein, direct evidence for ultrafast photothermal‐induced electrical behavior of a platinum microwire (Pt MW) illuminated by a focused laser beam and modulated at different frequencies (329 Hz, 10, 50, and 150 kHz) is provided. The obtained electrical behavior images indicate that Pt‐based structures can be used to develop a new type of photodetector, namely, a photo‐thermo‐electric (PTE) detector. A high photoresponsivity of 0.3 mA W−1 and a fast response time of ≈50 μs on a single 1 μm wide Pt PTE detector are obtained. To further amplify the PTE effect of Pt MW, an integrated array of Pt MWs and a coating of gold nanorods is combined into a hybrid PTE detector, achieving a higher responsivity close to 100 mA W−1, which is 300 times higher than that of a single Pt MW PTE detector. These results confirm that Pt‐based PTE devices are promising candidates for efficient and fast‐response photodetectors.