Enhanced Performance of Wideband Room Temperature Photodetector Based on Cd3As2 Thin Film/Pentacene Heterojunction

3D Dirac semimetal Cd3As2, as an ideal candidate photosensitive material, has attracted widespread attention due to its excellent characteristics of high carrier mobility and zero band gap. Although photodetector based on Cd3As2 crystal material has been made, there are still huge significances for the utilization of Cd3As2 thin film in commercial devices. In this paper, we demonstrated a wide band photodetector based on heterojunction of Cd3As2 thin film and pentacene for the first time. This photodetector can detect the radiation wavelength from 450 nm (visible region) to 10600 nm (long wave infrared region) at room temperature, exhibiting high current responsivity (36.15 mA/W) and external quantum efficiency (7.29%) at 650 nm, of which R-i is more than six times as high as previously reported that of crystalline Cd3As2 devices. Most interestingly, the far-infrared current responsivity of this detector at 10600 nm can reach 1.55 mA/W, which is extremely difficult for other 2D material detectors. Overall, the wide-wavelength photodetector based on the combined film using Cd3As2 and Pentacene is proved to possess superior performance for photodetector device application. Moreover, Cd3As2 thin film/pentacene heterojunction has an advantage in the manufacturing array devices, thus providing various possibilities for application of thin-film photodetector. The use of Cd3As2 thin film and organic molecules opens up a new path for the practical application of Cd3As2 materials.