Surface Vertical Multi-Emission Laser with Distributed Bragg Reflector Feedback from CsPbI₃ Quantum Dots

Quantum dots (QDs) laser has become an important way to solve micro-application problems in many fields. However, single wavelength distributed Bragg reflector (DBR) has many limitations in practical applications, such as signal transmission. How to realize multiwavelength DBR lasing output simply is a challenge. To achieve a stable multi-wavelength quantum dots laser in the near-infrared region, the perovskite CsPbI₃ QDs laser with DBR structure is developed in this paper. A tetragonal crystal structure with complete bonding information and no defect is explained by X-ray diffractions (XRD) and Raman spectrum. The cross-section morphology of the DBR laser and the surface morphology of QDs is measured by scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively. An elliptical light propagation field and a double wavelength laser radiation are obtained from the finite-difference time-domain (FDTD) simulation. The output of the three wavelength lasers at 770 nm, 823 nm, and 873 nm is measured. The emission time of a DBR laser is about 2 h, and the average fluorescence quantum yield is 60%. The cavity length selection and energy level model are put in place to clearly see the working mechanism. All the results suggest that an effective and stable CsPbI₃ quantum dots DBR laser is realized.