Fast Liquid Phase Epitaxial Growth for Perovskite Single Crystals**Supported by the National Key R&D Program of China (Grant Nos. 2017YFC0111500 and 2016YFB0401600), the National Natural Science Foundation Project (Grant Nos. 61775034, 61571124, and 61674029), International Cooperation Program of Jiangsu Province (Grant No. BZ2018056), and the NSFC Research Fund for International Young Scientists (Grant No. 61750110537).

Abstract

Semiconductors grown by the solution-processed method have shown low-cost, facile fabrication process and comparable performance. However, there are many reasons why it is difficult to achieve high quality films. For example, lattice constant mismatch is one of the problems when photovoltaic devices made of organ metallic perovskites. In this work, MAPbBr3 () perovskites single crystals grown on the surface of MAPbBr2.5Cl0.5 perovskites single crystals via liquid epitaxial growth method is demonstrated. It is found that when the lattice constants of the two perovskite single crystals are matched, another crystal can be grown on the surface of one crystal by epitaxial growth. The whole epitaxy growth process does not require high heating temperature and long heating time. X-ray diffraction method is used to prove the lattice plane of the substrate and the epitaxial grown layer. A scanning electron microscope is used to measure the thickness of the epitaxial layer. Compared with perovskite-based photodetectors without epitaxial growth layer, perovskite-based photodetectors with epitaxial growth layer have lower dark current density and higher optical responsibility.