Laser Terahertz Emission Microscope for Imaging Grain Heterogeneity: A Case Study of CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> Perovskite Semiconductors
Zhaoyu Liu,
Liang Luo,
Joongmok Park,
Richard H. J. Kim,
Zhaoning Song,
Deniz Turan,
Mona Jarrahi,
Yanfa Yan,
Jigang Wang
Affiliations
Zhaoyu Liu
Ames National Laboratory-USDOE, Ames, IA 50011, USA
Liang Luo
Ames National Laboratory-USDOE, Ames, IA 50011, USA
Joongmok Park
Ames National Laboratory-USDOE, Ames, IA 50011, USA
Richard H. J. Kim
Ames National Laboratory-USDOE, Ames, IA 50011, USA
Zhaoning Song
Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
Deniz Turan
Electrical and Computer Engineering, University of California–Los Angeles, Los Angeles, CA 90095, USA
Mona Jarrahi
Electrical and Computer Engineering, University of California–Los Angeles, Los Angeles, CA 90095, USA
Yanfa Yan
Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
Jigang Wang
Ames National Laboratory-USDOE, Ames, IA 50011, USA
Strong terahertz (THz) emission from the methylammonium lead iodide (MAPbI3) perovskite semiconductors has been observed following above-bandgap photoexcitation, yet local THz responses of crystalline microstructures are absent. We implement laser THz emission microscope (LTEM), yet-to-be applied to the perovskite semiconductors, as a novel and complementary tool to evaluate the electronic and grain heterogeneity of MAPbI3 thin films. Two MAPbI3 samples with different grain sizes are studied. Using this approach, we show that the one with a larger grain size gives more uniform THz radiation. More significant spatial THz intensity fluctuation is observed for the sample with a smaller grain size.
