Low-threshold single-mode laser in perovskite microdiscs direct-synthesized into planar microcavity

Low-threshold single-mode laser in CsPbBr3 microdiscs grown between two distributed Bragg reflectors (DBRs) is realized at room temperature. The CsPbBr3 microdiscs are directly synthesized on the surface of prepared first-half DBRs microcavity by a chemical vapor deposition method. This scheme avoids possible surface damage or contamination caused by the traditional transfer of sample into the DBRs. The single-mode laser with low threshold (∼1.3 μJ/cm2) was obtained in the CsPbBr3 microdiscs sandwiched in DBRs and measured by using the micro-photoluminescence spectroscopy. The length of the resonant cavity is short enough to support a large free spectral range, which ensures only one mode in the bandwidth of the optical gain. Moreover, by modulating the thickness of the CsPbBr3 microdiscs, the wavelength of single-mode laser emission can be broadly tuned from 529.6 to 544.1 nm. This work provides a method of fabricating single-mode laser in DBRs, which may have potential applications in on-chip integration of optoelectronic devices and signal processing.