Controlling band alignments by artificial interface dipoles at perovskite heterointerfaces

Abstract

The concept ‘the interface is the device' is embodied in a wide variety of interfacial electronic phenomena and associated applications in oxide materials, ranging from catalysts and clean energy systems to emerging multifunctional devices. Many device properties are defined by the band alignment, which is often influenced by interface dipoles. On the other hand, the ability to purposefully create and control interface dipoles is a relatively unexplored degree of freedom for perovskite oxides, which should be particularly effective for such ionic materials. Here we demonstrate tuning the band alignment in perovskite metal-semiconductor heterojunctions over a broad range of 1.7 eV. This is achieved by the insertion of positive or negative charges at the interface, and the resultant dipole formed by the induced screening charge. This approach can be broadly used in applications where decoupling the band alignment from the constituent work functions and electron affinities can enhance device functionality.

Designing functional ferroelectric interfaces from first-principles: dipoles and band bending at oxide heterojunctions

“…Therefore, we evaluated the magnitude of the interface dipoles in the systems under investigation, starting from the charge density difference data in figure 6 and solving the 1D Poisson equation for the electrostatic potential. Then, the microscopic interface dipole, δ dip , was evaluated as the potential drop at each interface [88,90]. Figure 11 displays the δ dip values for the thin electrode capacitors as a function of the VBM shift when the Ti 3s semi-core states are used as reference with respect to the band line-up scheme (see figure 9).…”

Quantum Dots for Hybrid Energy Harvesting: From Integration to Piezo‐Phototronics

“…Through strain engineering, local band structure and/or band alignment can be modulated, which consequently tunes junction properties. Since the first demonstration of the piezotronics, it has attracted tremendous research interests from interdisciplinary areas such as electronics, optoelectronics, and electrochemistry …”

Controlled Current Transport in Pt/Nb:SrTiO3 Junctions via Insertion of Uniform Thin Layers of TaOx

“…Reduction of the interfacial resistance is considered a crucial step for many electronic applications of STO, because STO's wide band gap (3.3 eV) easily forms a high (>1.0 eV) Schottky barrier with an electrode causing a high contact resistance. In metal/oxide junctions, interface engineering has also been demonstrated to be effective at reducing the barrier height . In SrRuO 3 /Nb:STO epitaxial junctions, formation of a good ohmic contact has been achieved by inserting a thin epitaxial LaAlO 3 interfacial layer .…”

“…In metal/oxide junctions, interface engineering has also been demonstrated to be effective at reducing the barrier height . In SrRuO 3 /Nb:STO epitaxial junctions, formation of a good ohmic contact has been achieved by inserting a thin epitaxial LaAlO 3 interfacial layer . For Pt, which is the most widely used electrode for oxides, however, no appropriate interface‐layer material has been proposed for ohmic contact formation.…”