Mechanism of rectification and two-type bipolar resistance switching behaviors of Pt /Pb(Zr_0.52Ti_0.48)O₃ /Nb:SrTiO₃

Resistive Switching and Modulation of Pb(Zr0.4Ti0.6)O3/Nb:SrTiO3 Heterostructures

“…The ferroelectric RS effect has been revealed in many ferroelectric thin films − and ferroelectric tunneling junctions (FTJs) based on ferroelectric ultrathin films. − Although the FTJs have been reproducibly demonstrated to present a remarkable resistive switching effect, the thickness requirement of the ferroelectric layer to be several nanometers greatly limits the potential applications . In addition, for typical ferroelectric ultrathin films, large lattice mismatch, size effect, and structural defects could damage the ferroelectricity and cause a large leakage current, which could make the switching signal unreadable. , On the other hand, excellent electric properties such as high ON/OFF ratio, good retention, and high endurance have been reported in relatively thick ferroelectric thin films, such as BiFeO 3 (BFO), , Pb­(Zr x Ti 1– x )­O 3 (PZT), , and BaTiO 3 (BTO). , For instance, Tsurumaki et al fabricated Pt/BFO (100 nm)/SrRuO 3 (SRO) layered structures on SrTiO 3 (STO) single-crystal substrates, and showed a ON/OFF ratio of above 1000. Hu et al reported a continuously tunable ON/OFF ratio up to 5000 in Pt/BFO (60 nm)/Nb-doped STO (NSTO) structure, which was attributed to the ferroelectric polarization modulation of the width of depletion layer at the BFO/NSTO interface.…”

“…The correlation between the ferroelectric RS behavior and ferroelectric polarization in the relatively thick ferroelectric films is different from that of the FTJs, and a variety of different microscopic mechanisms have been proposed to explain the resistive switching effect, such as the conductive filament type and the interface type modulated by ferroelectric polarization. However, the performance and mechanisms vary greatly, even for the same material and device structure. ,,, For these ferroelectric semiconducting films, the ferroelectricity and conductivity are directly determined by the thickness of ferroelectric films. To enhance the device performance, it is a main approach to modulate the potential barrier height or barrier thickness by ferroelectric polarization at the ferroelectric/electrode interfaces, which is also closely related to the thickness of ferroelectric films.…”

“…1 In addition, for typical ferroelectric ultrathin films, large lattice mismatch, size effect, and structural defects could damage the ferroelectricity and cause a large leakage current, which could make the switching signal unreadable. 7,11 On the other hand, excellent electric properties such as high ON/OFF ratio, good retention, and high endurance have been reported in relatively thick ferroelectric thin films, such as BiFeO 3 (BFO), 12,13 Pb(Zr x Ti 1−x )O 3 (PZT), 14,15 and BaTiO 3 (BTO). 4,16 For instance, Tsurumaki et al 12 fabricated Pt/BFO (100 nm)/ SrRuO 3 (SRO) layered structures on SrTiO 3 (STO) singlecrystal substrates, and showed a ON/OFF ratio of above 1000.…”

“…However, the performance and mechanisms vary greatly, even for the same material and device structure. 5,12,14,15 ferroelectric semiconducting films, the ferroelectricity and conductivity are directly determined by the thickness of ferroelectric films. To enhance the device performance, it is a main approach to modulate the potential barrier height or barrier thickness by ferroelectric polarization at the ferroelectric/electrode interfaces, which is also closely related to the thickness of ferroelectric films.…”