Enhancement in light absorption of InAs-thin-film photodetectors with metal nanowire grating

In this work, we have designed a novel surface structure for enhancing the optical absorption of the two-dimensional indium arsenide (InAs) photodetectors, with a combination of local light-field enhancement and coupled back reflection effect to break through the performance bottleneck of thin-film photodetectors. Through a finite element-based coupled opto-electronic simulation, our-proposed device has elevated light absorption and marked light field localization within the visible to near-infrared spectrum. Notably, it achieves a maximum absorption of 70.8% at wavelength of 780nm, which is 5.53 times that of the comparison sample. Moreover, the introduction of the metal grating structure has endowed our design with excellent photoelectrical response performance, namely a responsivity of 177.65 A·W^-1 , a specific detectivity of 1.367×10¹⁰ Jones, and a response time of 1.5 ns under a bias voltage of 0.01V. This work provides an effective strategy for enhancing the performance of two-dimensional photoconductive detectors and offers beneficial guidance for designing high-performance optoelectronic devices