Journal Article

Strain engineering and epitaxial stabilization of halide perovskites

Lo, Yu-Hwa, Li, Lain-Jong, Xu, Sheng, Wang, Chunfeng, Hu, Hongjie, Wang, Chonghe, Zhang, Zhuorui, Li, Yuheng, Qi, Baiyan, Yang, Kesong, Gu, Yue, Choi, Woojin, Lin, Muyang, Chiu, Ming-Hui, Cai, Jinze, Rao, Rahul, Dayeh, Shadi, Zhang, Jingxin, Maruyama, Benji, Song, Jiawei, Islam, Ahmad E., Yu, Yugang, Chen, Yimu, Li, Yang, Lei, Yusheng

2020

Overview

Strain engineering is a powerful tool with which to enhance semiconductor device performance 1 , 2 . Halide perovskites have shown great promise in device applications owing to their remarkable electronic and optoelectronic properties 3 – 5 . Although applying strain to halide perovskites has been frequently attempted, including using hydrostatic pressurization 6 – 8 , electrostriction 9 , annealing 10 – 12 , van der Waals force 13 , thermal expansion mismatch 14 , and heat-induced substrate phase transition 15 , the controllable and device-compatible strain engineering of halide perovskites by chemical epitaxy remains a challenge, owing to the absence of suitable lattice-mismatched epitaxial substrates. Here we report the strained epitaxial growth of halide perovskite single-crystal thin films on lattice-mismatched halide perovskite substrates. We investigated strain engineering of α-formamidinium lead iodide (α-FAPbI 3 ) using both experimental techniques and theoretical calculations. By tailoring the substrate composition—and therefore its lattice parameter—a compressive strain as high as 2.4 per cent is applied to the epitaxial α-FAPbI 3 thin film. We demonstrate that this strain effectively changes the crystal structure, reduces the bandgap and increases the hole mobility of α-FAPbI 3 . Strained epitaxy is also shown to have a substantial stabilization effect on the α-FAPbI 3 phase owing to the synergistic effects of epitaxial stabilization and strain neutralization. As an example, strain engineering is applied to enhance the performance of an α-FAPbI 3 -based photodetector. A method of deposition of mixed-cation hybrid perovskite films as lattice-mismatched substrates for an α-FAPbI 3 film is described, giving strains of up to 2.4 per cent while also stabilizing the metastable α-FAPbI 3 phase for several hundred days.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 140/133 / 140/146 / 142/126 / 639/301/299/946 / 639/301/357/995 / Compressive properties / Control / Crystal lattices / Crystal structure / Electric properties / Engineering / Epitaxial growth / Epitaxy / Halides / Hole mobility / Humanities and Social Sciences / Industrial engineering / Influence / Iodides / Iodine / Materials / Methods / multidisciplinary / Neutralization / Optical properties / Optoelectronic devices / Organic chemistry / Perovskite / Perovskites / Phase transitions / Science / Science (multidisciplinary) / Semiconductor films / Single crystals / Spectrum analysis / Stabilization / Strain analysis / Strains and stresses / Stress relaxation (Materials) / Stress relieving (Materials) / Substrates / Synergistic effect / Thermal expansion / Thin films