Hybrid organic–inorganic halide perovskites (HOIPs) have recently attracted tremendous attention because of their excellent semiconducting and optoelectronic properties, which exist despite their morphology and crystallinity being far inferior to those of more mature semiconductors, such as silicon and III–V compound semiconductors. Heteroepitaxy can provide a route to achieving high-performance HOIP devices when high crystalline quality and smooth morphology are required, but work on heteroepitaxial HOIPs has not previously been reported. Here, we demonstrate epitaxial growth of methylammonium lead iodide (MAPbI₃) on single crystal KCl substrates with smooth morphology and the highest carrier recombination lifetime (∼213 ns) yet reported for nonsingle crystalline MAPbI₃. Experimental Raman spectra agree well with theoretical calculations, presenting in particular a sharp peak at 290 cm^–1 for the torsional mode of the organic cations, a marker of orientational order and typically lacking in previous reports. Photodetectors were fabricated showing excellent performance, confirming the high quality of the epitaxial MAPbI₃ thin films. This work provides a new strategy to enhance the performance of all HOIPs-based devices.

中文翻译：

---

基于溶液外延生长的混合卤化物钙钛矿的高性能光电探测器

混合有机-无机卤化物钙钛矿（HOIP）最近因其优异的半导体和光电性能而备受关注，尽管它们的形貌和结晶度远不如更成熟的半导体（例如硅和III-V化合物半导体）。当需要高结晶质量和平滑形态时，异质外延可以提供一种实现高性能HOIP器件的途径，但是以前尚未报道过在异质外延HOIP上的工作。在这里，我们证明了甲基铵碘化铅（MAPbI ₃）在单晶KCl衬底上的外延生长，具有平滑的形态和最高的载流子复合寿命（〜213 ns），但尚未报道非单晶的MAPbI _3。。拉曼光谱实验与理论计算非常吻合，特别是在有机阳离子的扭转模式下，在290 cm ^–1处出现一个尖峰，这是取向顺序的标志，以前的报道中通常没有。所制造的光电探测器显示出优异的性能，证实了外延MAPbI ₃薄膜的高质量。这项工作为提高所有基于HOIP的设备的性能提供了一种新的策略。