Multicolor Photodetector of a Single Er(3+)-Doped CdS Nanoribbon

Er(3+)-doped CdS nanoribbons (Er-CdS NRs) are synthesized by thermal evaporation and then characterized by field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL), and absorption spectra. The Er-CdS NR photodetector is studied systematically, including spectral response, light intensity response, and photoconductance (G) versus temperature (T). It is found that Er-CdS NR has the ability of detecting multicolor light including blue, red, and near-infrared light with higher responsivity (R(λ)) and external quantum efficiency (η). The conductance of Er-CdS NR under dark conditions decreases with increasing temperature in the range of 87–237 K, while its conductance increases with increasing temperature in the range of 237–297 K when T is larger than 237 K. These results indicated that ionized impurities and the intrinsic excitation are responsible for the conductance change of Er-CdS NR in the dark. The superior performance of the Er-CdS NR device offers an avenue to develop highly sensitive multicolor photodetector applications. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s11671-015-0975-3) contains supplementary material, which is available to authorized users.