Direct observation of the leakage current in epitaxial diamond Schottky barrier devices by conductive-probe atomic force microscopy and Raman imaging

The origin of the high leakage current measured in several vertical-type diamond Schottky devices is conjointly investigated by conducting probe atomic force microscopy (CP-AFM) and confocal micro-Raman/Photoluminescence (PL) imaging analysis. Local areas characterized by a strong decrease of the local resistance (5-6 orders of magnitude drop) with respect to their close surrounding have been identified in several different regions of the sample surface. The same local areas, also referenced as electrical hot-spots, reveal a slightly constrained diamond lattice and three dominant Raman bands in the low-wavenumber region (590, 914 and 1040 cm-1). These latter bands are usually assigned to the vibrational modes involving boron impurities and its possible complexes that can electrically act as traps for charge carriers. Local current-voltage measurements performed at the hot-spots point out a trap-filled-limited (TFL) current as the main conduction mechanism favoring the leakage current in the Schottky devices

Thermoelectric infrared microsensor using suspended membranes made by silicon micromachining

International audienc

New developments on IR distribution-patterned microradiometers family

International audienc

Characterization of phosphorus and boron heavily doped LPCVD polysilicon films in the temperature range 293-373K

International audienc

Spatio-temporal observation of photogenerated electron dynamics in twisted graphene

Graphene is one of the most studied 2D materials. However, the ultrafast carrier dynamics influenced by the crystallographic structures is not well studied, because of the instrumental limitations. Locally different twisting angle between graphene layers was detected by Raman spectro-microscopy. Photogenerated carrier lifetimes in these selected regions were estimated by time-resolved photoemission electron microscopy with 100 nm spatial and 100 fs temporal resolutions. We concluded that the interaction between layers and to the substrate influence the optoelectronic properties