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June-Mo Yang1 2 Nam-Gyu Park1 2

1, Sungkyunkwan University, Suwon, SE, Korea (the Republic of)
2, Sungkyunkwan University Advanced Institute of NanoTechnology, Suwon, , Korea (the Republic of)

We report here on effect of HC(NH2)2PbI3 (FAPbI3) crystal structure on resistive switching behavior. We have fabricated Pt/FAPbI3/Ag(or Au) device for studying resistive switching behavior. Crystal structure of FAPbI3 crystal is changed by different annealing temperature. Black alpha phase FAPbI3 is obtained at high temperature, while yellow delta phase can be obtained at relatively lower temperature. RESET failure of 1st sweep occurs in I-V curve for alpha phase, whereas much better resistive switching property is observed from delta phase. XRD analysis reveals that (0k0) planes are dominant for delta phase, which indicates that (0k0) planes are aligned in parallel with metal electrode. Thus, conducting filament might be formed perpendicular to (0k0) plane. DFT calculation support our assumption, where we confirm that activation energy of iodide migration in <0k0> direction of delta phase is 0.4 eV but in-plane iodide migration requires higher activation energy of about 0.9 eV. Since switching behavior can be influenced by film morphology, we have measured surface and cross-sectional scanning electron microscopy, but pin-hole-free with smooth surface is confirmed. SET voltage of the device based on delta phase FAPbI3 occurs near 0.20 V and RESET voltage is less than -0.4 V. ON/OFF switching takes places over 1000 cycles with ON/OFF ratio being close to 106. Multilevel data storage is also confirmed by changing compliance current from 10-2 to 10-5 A. Long retention time of more than 2000 s is exhibited from low-temperature delta phase FAPbI3

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