Crystallization mechanism and lasing properties of CsPbBr₃ perovskites by chemical vapor deposition

The chemical vapor deposition (CVD) technique is widely used in industry for growing perovskite materials with high crystalline quality and low defect density. However, the underlying crystallization mechanism of all-inorganic lead halide perovskites during the implementation of the CVD process has not been clearly revealed. Under this direction, in this work, hemispheric, rod-shaped, plate-shaped, triangular pyramid-shaped, and irregular-shaped, etc. cesium lead bromide (CsPbBr₃) perovskite microcavities were obtained by adjusting the local temperature distribution, substrate types, deposition position, carrier gas flow rate (CGFR), and air pressure within the tube furnace. The crystallization mechanism for the CsPbBr₃ microcavity growth with different shapes, densities, and sizes was investigated. It can be seen from the scanning electron microscope (SEM) images that micron hemispheres can be obtained at 5.5 to 6.5 cm (1 0 0) Si substrates at standard atmospheric pressure and high deposition temperatures. On the contrary, at low deposition temperatures, microrods, microplates, and microcuboids can be fabricated on the (1 1 1) Si, (1 0 0) Si, and indium tin oxide (ITO) substrates, respectively, without carrier gas flow and air pressure. We can also modulate the size of the micron hemispheres and microplates by altering the deposition position and CGFR. Moreover, the lasing characteristics of the microplate, microrod, and microcuboid were examined by photoluminescence (PL) and time-resolved PL (TRPL) measurements. Our work provided a feasible method to control the crystal sizes, cavity shapes, and optical properties for the development of various types of lead halide perovskites.