Near-infrared photodetectors based on unique Fe2O3 nanorod array with multi-photon excitation

Abstract

Due to wide applications in imaging and optical communications, how to develop novel high quality and low-cost candidate materials for near-infrared (NIR) photodetectors has become a hot research topic in recent years. Here, the self-powered NIR photodetector based on novel diamond randomly staggered α-Fe 2 O 3 nanorod array is reported, which exhibits a dark current of 1.0 nA and photocurrent of 0.85 μA at 1.8 W @ 1 V, 40 ℃ with an NIR light irradiation on the novel α-Fe 2 O 3 film. The experimental curve of photocurrent with light intensity is fitted based on equation of I ph = C 1 P α , and the exponent α is estimated to have a value of 4.0, implying that there exists a four-photon excitation process under irradiation with wavelength of 808 nm. Furthermore, the J - V characteristics at different substrate temperatures are investigated, and the Arrhenius plot of current density vs temperature shows that the activation energy is about 0.58 eV under dark, but is reduced to 0.32 eV under NIR illumination. Above characteristic of the obtained high NIR photoelectric response can be probably attributed to the synergetic effect of strong light absorption and oxygen vacancies. • The self-powered NIR photodetector based on novel randomly staggered α-Fe 2 O 3 nanorod array was realized. • A multi-photon process was observed due to the strong light absorption in randomly staggered α-Fe 2 O 3 nanorod array. • The high NIR photoelectric response was realized by the synergetic effect of strong light absorption and sub-level state of oxygen vacancies.