Potential barrier increase due to Gd doping of BiFeO3 layers in Nb:SrTiO3-BiFeO3-Pt structures displaying diode-like behavior

Abstract

The rectifying properties of Nb:SrTiO 3-Bi 1Àx Gd x FeO 3-Pt structures (x ¼ 0, 0.05, 0.1) displaying diode-like behavior were investigated via current-voltage characteristics at different temperatures. The potential barrier was estimated for negative polarity assuming a Schottky-like thermionic emission with injection controlled by the interface and the drift controlled by the bulk. The height of the potential barrier at the Nb:SrTiO 3-Bi 1Àx Gd x FeO 3 interface increases with Gd doping. The results are explained by the partial compensation of the p-type conduction due to Bi vacancies with Gd doping in addition to the shift of the Fermi level towards the middle of the bandgap with increasing dopant concentration. V

Ferroelectric memristor based on Pt/BiFeO3/Nb-doped SrTiO3 heterostructure

“…1(b) reveals that the p-n junction at BFO/NSTO interface dominates the transport properties of Pt/BFO/NSTO/In heterostructure, while the Schottky barrier at Pt/BFO interface is negligible, which is consistent with the prior reports. 12,16,19 To investigate the bistable resistive switching in our heterostructure, we applied positive (þ6 V) and negative (À10 V) pulse voltages (V write ) with 1 ms width to polarize the ferroelectric BFO downward and upward, respectively, and then measured the current at low reading voltages V read (jV read j 0.5 V ( jV write j). These I-V curves are shown in Fig.…”

Carrier accumulation near electrodes in ferroelectric films due to polarization boundary conditions

“…[1][2][3][4][5][6] The presence of FE polarization alters the classical characteristics of film-electrode junctions in an otherwise linear dielectric semiconductor, making polarization manipulation of carriers possible [6][7][8][9] but at the expense of potential leakage currents. [10][11][12][13][14][15] For this very reason, electrical and polarization boundary conditions (BCs) at the film-electrode interface become crucially important parameters that determine the functionality of these systems almost regardless of film thickness. Significant number of studies have been devoted to clarifying the effect of semiconducting properties of FEs on their hystereses, capacitance-voltage, and current-voltage behavior, 4,16,2,3,10,11,13,[17][18][19][20][21] where the only difference is apparently the consideration of an additional built-in field due to polarization inserted to the equations next to the built-in field due to the Schottky character of the junction.…”

“…[10][11][12][13][14][15] For this very reason, electrical and polarization boundary conditions (BCs) at the film-electrode interface become crucially important parameters that determine the functionality of these systems almost regardless of film thickness. Significant number of studies have been devoted to clarifying the effect of semiconducting properties of FEs on their hystereses, capacitance-voltage, and current-voltage behavior, 4,16,2,3,10,11,13,[17][18][19][20][21] where the only difference is apparently the consideration of an additional built-in field due to polarization inserted to the equations next to the built-in field due to the Schottky character of the junction. 10,11,13,22 A number of other works adopt thermodynamic approaches coupled with electrostatics and semiconductor equations for a given FE-electrode couple.…”

“…Significant number of studies have been devoted to clarifying the effect of semiconducting properties of FEs on their hystereses, capacitance-voltage, and current-voltage behavior, 4,16,2,3,10,11,13,[17][18][19][20][21] where the only difference is apparently the consideration of an additional built-in field due to polarization inserted to the equations next to the built-in field due to the Schottky character of the junction. 10,11,13,22 A number of other works adopt thermodynamic approaches coupled with electrostatics and semiconductor equations for a given FE-electrode couple. [23][24][25][26][27][28][29][30] While the importance of electrical and polarization BCs on properties of FE films is very well anticipated, only a handful of relatively recent studies have seriously tried to address their impact on the properties.…”

Interface electronic structure in a metal/ferroelectric heterostructure under applied bias

“…Such measurements under applied bias are even more challenging. Several groups have conducted electrical measurement on these systems 9,11,12 but they do not directly probe the microscopic interfacial electronic structure. X-ray photoelectron spectroscopy (XPS) can reveal the electronic structure.…”