Photoelectric Parameters of Photodetectors Based on Thin Microcrystalline Films of CH 3 NH 3 PbI 3 Perovskite
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lectric Parameters of Photodetectors Based on Thin Microcrystalline Films of CH3NH3PbI3 Perovskite D. V. Amaseva, K. A. Savinb,c*, and S. N. Nikolaevc a
Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow, 119991 Russia b Moscow State University, Moscow, 119991 Russia c Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 119991 Russia *e-mail: [email protected] Received March 27, 2020; revised April 3, 2020; accepted April 3, 2020
Abstract—Photoelectric characteristics of photodetectors of the type of a photoresistor based on microcrystalline films of the organometallic perovskite CH3NH3PbI3 with gold and aluminum contacts have been studied. The maximum photosensitivity of the photodetectors was 30 A/W. The buildup and decay times of the photoconductivity were in the range from 2.6 to 25.5 μs. Keywords: photodetectors, organometallic perovskites, photosensitivity, photoconductivity. DOI: 10.1134/S1063785020070020
Organometallic perovskites based on CH3NH3PbI3 (or MAPbI3) are promising materials for solar cell arrays, photodetectors, transistors, and lasers. The strong interest in this material is due to its outstanding properties, such as an energy gap width that is optimal for development of solar cells (1.6 eV) and high mobility and long lifetime of carriers, which are the key characteristics for optoelectronic devices. In particular, a large number of reports can be found in the literature that are concerned with parameters of photodetectors based on both single-crystal and microcrystalline perovskite MAPbI3 [1]. Thus far, photoconductivity buildup and decay times in the range from 10 ms to 100 ns have been reached, with the spectral photosensitivity being as high as several hundreds of A/W. However, high-tech installations are used to fabricate such photodetectors, the structure of the photodetectors themselves is complex, and high electric field strengths and incident light intensities are required. Despite the large number of scientific reports, including those of review type [1–4], concerned with parameters of perovskite-based photodetectors, attempts to create a device that would be accessible and comparatively simple to fabricate remain topical. Therefore, we examined in this study the photoelectric properties of a perovskite-based device of photoresistive type produced in the simplest and most feasible way.
Thin films of MAPbI3 perovskite were prepared by a single-stage method from MAI and PbI2 [5]. The resulting perovskite films had a thickness of ~350 nm and a microcrystalline structure. Contacts were deposited above the perovskite films by thermal evaporation in a vacuum in the interdigitate configuration. Gold served as the contact material for photodetector no. 1 (PD1), and aluminum served as such for photodetector no. 2 (PD2) (chosen on the basis of considerations of material availability). The distances between the contacts for PD1 and PD2 were, respectively, 130 and 280 μm, and the contact lengths were 8.55 and 19 mm. Thus, the sensitive part area of PD
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