First-principles investigation of oxidized Si- and Ge-terminated diamond (100) surfaces.

Diamond is a semiconductor material with remarkable structural, thermal, and electronic properties that has garnered significant interest in the field of electronics. Although hydrogen (H) and oxygen (O) terminations are conventionally favored in transistor designs, alternative options, such as silicon (Si) and germanium (Ge), are being explored because of their resilience to harsh processing conditions during fabrication. Density-functional theory was used to examine the non-oxidized and oxidized group-IV (Si and Ge)-terminated diamond (100) surfaces.

Heteroatom Functionalization of H-Terminated Diamond Surfaces.

Diamond surface functionalization has received significant research interest recently. Specifically, H-termination has been widely adopted because it endows the diamond surface with negative electron affinity and the hole carrier is injected in the presence of surface transfer dopants. Exploring different functional groups' attachment on diamond surfaces and their impact on the electronic structure, using wet and dry chemical approaches, would hence be of interest in engineering diamond as a semiconductor.

Phase Stability of Hexagonal/Cubic Boron Nitride Nanocomposites.

Boron nitride (BN) is an exceptional material, and among its polymorphs, two-dimensional (2D) hexagonal and three-dimensional (3D) cubic BN (h-BN and c-BN) phases are most common. The phase stability regimes of these BN phases are still under debate, and phase transformations of h-BN/c-BN remain a topic of interest. Here, we investigate the phase stability of 2D/3D h-BN/c-BN nanocomposites and show that the coexistence of two phases can lead to strong nonlinear optical properties and low thermal conductivity at room temperature.

Tunable Thermal Energy Transport across Diamond Membranes and Diamond-Si Interfaces by Nanoscale Graphoepitaxy.

The development of electronic devices, especially those that involve heterogeneous integration of materials, has led to increased challenges in addressing their thermal operational temperature demands. The heat flow in these systems is significantly influenced or even dominated by thermal boundary resistance at the interface between dissimilar materials. However, controlling and tuning heat transport across an interface and in the adjacent materials has so far drawn limited attention.

Nanosecond transient absorption studies of the pH-dependent hydrated electron quenching by HSO.

The large standard reduction potential of an aqueous solvated electron (eaq-, E° = -2.9 V) makes it an attractive candidate for reductive treatment of wastewater contaminants. Using transient absorption spectroscopy, the nanosecond to microsecond dynamics of eaq- generated from 10 mM solutions of Na2SO3 at pH 4 to 11 in H2O and D2O are characterized, resulting in the determination that between pH 4 and 9 it is the HSO3-, and not H+ as previously postulated by others, that effectively quenches eaq-.

Ultrathin single crystal diamond nanomechanical dome resonators.

We present the first nanomechanical resonators microfabricated in single-crystal diamond. Shell-type resonators only 70 nm thick, the thinnest single crystal diamond structures produced to date, demonstrate a high-quality factor (Q ≈ 1000 at room temperature, Q ≈ 20 000 at 10 K) at radio frequencies (50-600 MHz). Quality factor dependence on temperature and frequency suggests an extrinsic origin to the dominant dissipation mechanism and methods to further enhance resonator performance.

Note: Laser ablation technique for electrically contacting a buried implant layer in single crystal diamond.

The creation of thin, buried, and electrically conducting layers within an otherwise insulating diamond by annealed ion implantation damage is well known. Establishing facile electrical contact to the shallow buried layer has been an unmet challenge. We demonstrate a new method, based on laser micro-machining (laser ablation), to make reliable electrical contact to a buried implant layer in diamond.