Electrical properties of ZnO–BaTiO3–ZnO heterostructures with asymmetric interface charge distribution

Abstract

We report on capacitance-voltage, current-voltage, Sawyer-Tower, and transient current switching measurements for a ZnO-BaTiO 3-ZnO heterostructure deposited on ͑001͒ silicon by using pulsed laser deposition. The triple-layer structure reveals asymmetric capacitance-and current-voltage hysteresis and cycling-voltage dependent Sawyer-Tower polarization drift. We explain our findings by coupling of the ferroelectric ͑BaTiO 3 ͒ and piezoelectric ͑ZnO͒ interface charges and parallel polarization orientation of the ZnO layers causing asymmetric space charge region formation under positive and negative bias. The transient current characteristics suggest use of this structure as nonvolatile memory device.

Interface polarization coupling in piezoelectric-semiconductor ferroelectric heterostructures

“…Brief biasing by short voltage pulses here switch the bijunction heterostructure into situations ͑i͒ or ͑ii͒ and in which the heterostructure static series resistance is slightly different, e.g., at a given "read" voltage of 1 V. Bistable switching operation of this heterostructure was presented recently. 59 A similar switching behavior was observed previously in metal-ferroelectric-metal heterostruc layer dielectric continuum model calculations augmented by parallel circuits of diode-resistance pairs that such hysteresis offset can occur due to asymmetric resistance changes. In their series model, two pairs of antiparallel oriented diodes with two different resistances mimic the effect of different leakage currents within the ferroelectric layer over the metal interface barriers into the metal contacts.…”

“…11 In our heterostructures, the diodelike behavior originates from the variation in the depletion layers and the ferroelectric polarization. 59 The PFP heterostructures discussed in our work possess potential for new ferroelectric-semiconductor thin-film device applications.…”

“…Structural, optical, and electrical analysis were performed as described previously. 12,[54][55][56][57][58][59] The ZnO layers are n-type conductive, with free electron concentration N c between 1 ϫ 10 16 -1 ϫ 10 17 cm −3 . Net donor densities were determined by electrical Hall effect and Infrared Ellipsometry characterization.…”

Ba-DOPED ZnO MATERIALS: A DFT SIMULATION TO INVESTIGATE THE DOPING EFFECT ON FERROELECTRICITY

“…30 Transition metals make a multiferroic semiconductor. In particular, Ba-doped ZnO material has not been largely studied, since just ZnO/BaTiO 3 heterojunction [31][32][33][34] and BaO/ZnO interfaces 35 have been recently investigated. The most common atoms inserting in the ZnO structure are N, 36,37 Pd, 37 Mg, 38 Gd 39 atoms and lanthanide metals.…”

Intrinsic asymmetric ferroelectricity induced giant electroresistance in ZnO/BaTiO3 superlattice

“…[14][15][16][17] Coupling between the piezoelectric ZnO and the ferroelectric BaTiO 3 may cause bistable ferroelectric polarization orientation. [18][19][20][21][22] The piezoelectric ZnO has an inherent polarization which is difficult to reverse using an electric eld, but the polarization of ferroelectric BaTiO 3 can be reversed in experiments. The parallel or antiparallel polarizations of ZnO and BaTiO 3 may lead to intrinsic asymmetric ferroelectricity in the ZnO/BaTiO 3 superlattice which is similar to that found in tricolor superlattices.…”