Vacuum‐Vapor‐Deposited 0D/3D All‐Inorganic Perovskite Composite Films toward Low‐Threshold Amplified Spontaneous Emission and Lasing

Abstract Vacuum vapor deposition (VVD) is a promising way to advancing the commercialization of perovskite light sources owing to its convenience for wafer‐scale mass production and compatibility with silicon photonics manufacturing infrastructure. However, the light emission performance of VVD‐grown perovskites still lags far behind that of the conventional solution‐processed counterparts due to their inferior luminescence properties. Here, a 0D/3D cesium–lead–bromide perovskite composite film is prepared on Si/SiO₂ substrates through composition modulation with the VVD method, which exhibits an ultralow amplified spontaneous emission (ASE) threshold down to 14.3 µJ cm⁻² in the optimal films, which is on par with that of the solution‐processed counterparts. Meanwhile, they also display intriguing operational stability with negligible emission intensity decay under continuous excitation above ASE threshold for 4 h in the air. The outstanding ASE performance mainly originates from the reduced trap density and weakened electron–phonon coupling in the 3D CsPbBr₃ phase enabled by the incorporation of the 0D Cs₄PbBr₆ phase. Finally, by integrating the composite film with the distributed feedback (DFB) cavity, DFB lasing is achieved with a low threshold of 18.2 µJ cm⁻² under nanosecond‐pulsed laser pumping, which highlights the potential of VVD‐processed perovskites for developing high‐performance lasers.