Chlorine-Doped ZnSe Nanoribbons with Tunable n-Type Conductivity as High-Gain and Flexible Blue/UV Photodetectors

Although significant progress has been achieved in the fabrication of ZnSe nanostructures with various structures and morphologies, it remains a major challenge to rationally tune their transport properties for applications in future nano-optoelectronic devices. The synthesis of chlorine-doped ZnSe nanoribbons (NRs) with tunable n-type conductivity is achieved by a thermal co-evaporation method. The ZnSe:Cl NRs have single-crystal wurtzite structure and [120] orientation, which also show high crystalline quality and structural integrity comparable with the undoped NRs. Electrical measurements on a single ZnSe:Cl NR reveal a substantial enhancement of the conductivity upon Cl doping. The conductivity could be further tuned by adjusting the doping level. In addition, highly sensitive blue/UV photodetectors are constructed based on the ZnSe:Cl NRs. The devices exhibit an extremely high gain of approximately 106, and the UV response could be enhanced through a fast annealing process in air. By replacing the rigid SiO2/Si substrate with a PET substrate, flexible ZnSe:Cl NR photodetectors with excellent stability and durability under strain are realized. It is expected that the ZnSe:Cl NRs with tunable n-type conductivity will have important applications in the new generation nano-optoelectronic devices.