Quantum tailoring of electronic properties in covalently functionalized graphene: application to ammonia gas detection.

Functionalized graphene offers great potential in the field of rapid detection of gases at room temperature. We performed first-principles calculations to study the suitability of 4-sulfobenzenediazonium salts (4SBD) as bandgap modifier in graphene. The signature of unpaired spins is evidenced near the Fermi level owing to the symmetry breaking of graphene sublattices.

Anharmonicity and Disorder in the Black Phases of Cesium Lead Iodide Used for Stable Inorganic Perovskite Solar Cells.

Hybrid organic-inorganic perovskites emerged as a new generation of absorber materials for high-efficiency low-cost solar cells in 2009. Very recently, fully inorganic perovskite quantum dots also led to promising efficiencies, making them a potentially stable and efficient alternative to their hybrid cousins. Currently, the record efficiency is obtained with CsPbI, whose crystallographical characterization is still limited.

Symmetry-Based Tight Binding Modeling of Halide Perovskite Semiconductors.

On the basis of a general symmetry analysis, this paper presents an empirical tight-binding (TB) model for the reference Pm-3m perovskite cubic phase of halide perovskites of general formula ABX. The TB electronic band diagram, with and without spin orbit coupling effect of MAPbI has been determined based on state of the art density functional theory results including many body corrections (DFT+GW). It affords access to various properties, including distorted structures, at a significantly reduced computational cost.

Intrinsic interface states in InAs-AlSb heterostructures.

We examine the formation of intrinsic interface states bound to the plane of In-Sb chemical bonds at InAs-AlSb interfaces. Careful parameterization of the bulk materials in the frame of the extended-basis spds (*)tight-binding model and recent progress in predictions of band offsets severely limit the span of tight-binding parameters describing this system. We find that a heavy-hole-like interface state bound to the plane of In-Sb bonds exists for a large range of values of the InSb-InAs band offset.

Theoretical and experimental studies of (In,Ga)As/GaP quantum dots.

(In,Ga)As/GaP(001) quantum dots (QDs) are grown by molecular beam epitaxy and studied both theoretically and experimentally. The electronic band structure is simulated using a combination of k·p and tight-binding models. These calculations predict an indirect to direct crossover with the In content and the size of the QDs.