Growth and Characterization of Single-Crystal Lead Halide Perovskites for X-Ray Detector Application

Abstract

Growth and characterization of methylammonium lead iodide (MAPbI3) single crystals for X-ray detector application are reported. The inverse temperature crystallization (ITC) technique was employed to grow large-size bulk crystals by repeated seeding. By optimizing the molar ratio of starting materials and strictly controlling the solvent and growth temperatures, up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10\times 10\times $ </tex-math></inline-formula> 3 mm dimension single crystals with different natural facets were obtained. The optical bandgap was 1.49 eV as determined from the Tauc plot. We evaporated gold electrode on the top and bottom sides of the (100) crystal facet to fabricate a planar-type detector. The bulk resistivity of the crystal was estimated to be <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5\times 10^{7} \Omega \cdot {\mathrm{ cm}}$ </tex-math></inline-formula> from the current–voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$I$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V$ </tex-math></inline-formula> ) measurement at room temperature and in dark conditions. The X-ray detection test further confirmed that these detectors show strong and stable X-ray responses. These results suggest an easy and low-cost method to obtain large-area and shaped single crystals for future X-ray detector development.