Amorphous nitride semiconductors with highly tunable optical and electronic properties: the benefits of disorder in Ca-Zn-N thin films.

Semiconducting ternary nitrides are a promising class of materials that have received increasing attention in recent years, but often show high free electron concentrations due to the low defect formation energies of nitrogen vacancies and substitutional oxygen, leading to degenerate n-type doping. To achieve non-degenerate behavior, we now investigate a family of amorphous calcium-zinc nitride (Ca-Zn-N) thin films. By adjusting the metal cation ratios, we demonstrate band gap tunability between 1.

Broad Range Tuning of InAs Quantum Dot Emission for Nanophotonic Devices in the Telecommunication Bands.

InAs semiconductor quantum dots (QDs) emitting in the near-infrared are promising platforms for on-demand single-photon sources and spin-photon interfaces. However, the realization of quantum-photonic nanodevices emitting in the telecom windows with similar performance remains an open challenge. In particular, nanophotonic devices incorporating quantum light emitting diodes in the telecom C-band based on GaAs substrates are still lacking due to the relaxation of the lattice constant along the InGaAs graded layer which makes the implementation of electrically contacted devices challenging.

Ligand-Tuned AgBiS Planar Heterojunctions Enable Efficient Ultrathin Solar Cells.

AgBiS quantum dots (ABS QDs) have emerged as highly promising candidates for photovoltaic applications due to their strong sunlight absorption, nontoxicity, and elemental availability. Nevertheless, the efficiencies of ABS solar cells currently fall far short of their thermodynamic limits due in large part to sluggish charge transport characteristics in nanocrystal-derived films. In this study, we overcome this limitation by tuning the surfaces of ABS semiconductor QDs via a solvent-induced ligand exchange (SILE) strategy and provide key insights into the role of surface composition on both - and -type charge transfer doping, as well as long-range charge transport.

Zirconium Oxynitride Thin Films for Photoelectrochemical Water Splitting.

Transition metal oxynitrides are a promising class of functional materials for photoelectrochemical (PEC) applications. Although these compounds are most commonly synthesized via ammonolysis of oxide precursors, such synthetic routes often lead to poorly controlled oxygen-to-nitrogen anion ratios, and the harsh nitridation conditions are incompatible with many substrates, including transparent conductive oxides. Here, we report direct reactive sputter deposition of a family of zirconium oxynitride thin films and the comprehensive characterization of their tunable structural, optical, and functional PEC properties.

Tuning Carbon Dioxide Reduction Reaction Selectivity of Bi Single-Atom Electrocatalysts with Controlled Coordination Environments.

Control over product selectivity of the electrocatalytic CO reduction reaction (CORR) is a crucial challenge for the sustainable production of carbon-based chemical feedstocks. In this regard, single-atom catalysts (SACs) are promising materials due to their tunable coordination environments, which could enable tailored catalytic activities and selectivities, as well as new insights into structure-activity relationships. However, direct evidence for selectivity control via systematic tuning of the SAC coordination environment is scarce.

Solution-based synthesis of wafer-scale epitaxial BiVO thin films exhibiting high structural and optoelectronic quality.

We demonstrate a facile approach to solution-based synthesis of wafer-scale epitaxial bismuth vanadate (BiVO) thin films by spin-coating on yttria-stabilized zirconia. Epitaxial growth proceeds solid-state transformation of initially formed polycrystalline films, driven by interface energy minimization. The (010)-oriented BiVO films are smooth and compact, possessing remarkably high structural quality across complete 2'' wafers.

Influence of environmental conditions and surface treatments on the photoluminescence properties of GaN nanowires and nanofins.

Due to their intrinsically large surface-to-volume ratio, nanowires and nanofins interact strongly with their environment. We investigate the role of the main air constituents nitrogen, oxygen and water on the efficiency of radiative recombination in GaN nanostructures as a function of different surface treatments and at temperatures up to 200 °C. Oxygen and water exposures exhibit a complex behavior as they can both act quenching and enhancing on the photoluminescence intensity dependent on the temperature.