Absolute energy levels in nanodiamonds of different origins and surface chemistries.

Nanodiamonds (NDs) are versatile, broadly available nanomaterials with a set of features highly attractive for applications from biology over energy harvesting to quantum technologies. synthesis and surface chemistry, NDs can be tuned from the sub-micron to the single-digit size, from conductive to insulating, from hydrophobic to hydrophilic, and from positively to negatively charged surface by simple annealing processes. Such ND diversity makes it difficult to understand and take advantage of their electronic properties.

Electron Transport Properties in High Electron Mobility Transistor Structures Improved by V-Pit Formation on the AlGaN/GaN Interface.

This work suggests new morphology for the AlGaN/GaN interface which enhances electron mobility in two-dimensional electron gas (2DEG) of high-electron mobility transistor (HEMT) structures. The widely used technology for the preparation of GaN channels in AlGaN/GaN HEMT transistors is growth at a high temperature of around 1000 °C in an H atmosphere. The main reason for these conditions is the aim to prepare an atomically flat epitaxial surface for the AlGaN/GaN interface and to achieve a layer with the lowest possible carbon concentration.

Relation between Ga Vacancies, Photoluminescence, and Growth Conditions of MOVPE-Prepared GaN Layers.

A set of GaN layers prepared by metalorganic vapor phase epitaxy under different technological conditions (growth temperature carrier gas type and Ga precursor) were investigated using variable energy positron annihilation spectroscopy (VEPAS) to find a link between technological conditions, GaN layer properties, and the concentration of gallium vacancies (V). Different correlations between technological parameters and V concentration were observed for layers grown from triethyl gallium (TEGa) and trimethyl gallium (TMGa) precursors. In case of TEGa, the formation of V was significantly influenced by the type of reactor atmosphere (N or H), while no similar behaviour was observed for growth from TMGa.

Ultrathin Nanocrystalline Diamond Films with Silicon Vacancy Color Centers via Seeding by 2 nm Detonation Nanodiamonds.

Color centers in diamonds have shown excellent potential for applications in quantum information processing, photonics, and biology. Here we report chemical vapor deposition (CVD) growth of nanocrystalline diamond (NCD) films as thin as 5-6 nm with photoluminescence (PL) from silicon-vacancy (SiV) centers at 739 nm. Instead of conventional 4-6 nm detonation nanodiamonds (DNDs), we prepared and employed hydrogenated 2 nm DNDs (zeta potential = +36 mV) to form extremely dense (∼1.