Reaction and Energy Levels at Oxide–Oxide Heterojunction Interfaces

Abstract

Oxide–oxide heterojunction interfaces (OHIs) are foundations for many applications such as transistors, optoelectronic devices, and chemical catalysis. The formation of OHIs involves complex events such as charge transfer, interfacial diffusion, and chemical reactions. These events collectively contribute to an OHI's energy structure and to its ability to perform an intended application. Here, multiple MoO3/oxide interfaces are studied at which changes in multiple oxidation states Mox+ can be easily tracked. For the formation of reactive interfaces, it is found that the primary driving force behind the reduction of MoO3 is redox reactions at the interfaces. For the nonreactive interface, the reduction of MoO3 occurs as a result of various factors such as oxygen deficiency. At these OHIs, band bending and formation of interface dipole are observed. It is discovered that the degrees of interface dipole and work function at the OHIs scale linearly as a function of the contacting oxide's work function. These findings provide the guide in designing OHIs for a specific application.

Interface matters: Design of an efficient α-Ag2WO4/Ag3PO4 photocatalyst

“…The presence of W 5+ in the AWP 2 sample can arise from interfacial strain due to lattice mismatch between α-Ag2WO4 and Ag3PO4, since this latter was grown upon the α-Ag2WO4 particles. Furthermore, the W 6+ reduction can be assigned to the charge transfer effect between α-Ag2WO4 and Ag3PO4 due to the effective formation of the heterojunction that leads to the energy level alignment (Kung, Li et al 2019). It is well known that the photocatalytic activity of the photocatalysts is closely related to their light absorption ability, thus UV-vis diffuse reflectance spectroscopy is employed to determine the optical absorption properties of the pure Ag3PO4, α-Ag2WO4, and α-Ag2WO4/Ag3PO4 heterojunction.…”

Molecule Charge Transfer Doping for p‐Channel Solution‐Processed Copper Oxide Transistors

“…We speculated the reason to the large amount of oxygen vacancies in thermal evaporated MoO 3 films in a high vacuum chamber. [ 23 ] Once MoO 3 was contacted to Cu x O, the oxygen atoms in Cu x O could be diffused into MoO 3 , [ 24 ] leaving the oxygen vacancies (electron donors) inside the Cu x O channel. To confirm this, we further deposited MoO 3 onto the top of the n‐channel InGaZnO TFTs and clear n‐doping behavior was observed (Figure S10c, Supporting Information).…”

High Rejection‐Ratio IGZO Ultraviolet Phototransistor via Additional Solution Processed ZnO Absorption Layer

“…The high temperature required in the annealing process can lead to ion diffusion, carrier trapping due to interface states, and the formation of a mixed layer. [25] In this study, we designed ZnO nanoparticles (NPs) as an additional absorption layer in IGZO TFT for an ultraviolet-light phototransistor. The process utilizing ZnO NPs as the absorption layer occurs at a relatively low temperature of 200 °C, thereby avoiding issues such as ion diffusion.…”

“…The high temperature required in the annealing process can lead to ion diffusion, carrier trapping due to interface states, and the formation of a mixed layer. [ 25 ]…”