Observation of Superfluorescence of ZnO Nanosheets

Abstract

ZnO nanostructures are attractive candidates as source media for realizing optoelectronic devices. Based on the comparison of cathodoluminescence images and scanning electron microscope morphology images, the mixing color images of ZnO nanosheets indicate that the emission of the ZnO nanosheet is emitted from its flat surface. In time‐resolved photoluminescence, a sharp emission pulse is observed after the delay time τD of 56 ps relative to zero time at the threshold excitation power, the pulse peak intensity exhibits a superlinear increase proportional to P2.7 (P is the excitation power density), the reduction of τD is proportional to , oscillation is demonstrated in the decay trace at high excitation power, and the time interval of two oscillation emissions is 36 ps. Experimental results indicate that superfluorescence (SF) is demonstrated at room temperature and it is assigned to coherent dipole states in the population version localized to approximately 3 nm thick ZnO nanosheet. SF of coherent dipole states is characterized by the delay time τD—the unique feature of SF and the Burnham–Chiao ringing behavior. Experimental observation of SF of ZnO nanosheets may have potential value for the investigation of room temperature many‐body quantum phenomena, coherent control, and applications for high‐performance optoelectronic devices.