Compositional and electrical characterisation of the hydrogen-oxygen terminated diamond (100) surface

In this work (100) diamond films are hydrogenated using a conventional MWPE-CVD (microwave plasma enhanced chem. vapor deposition) reactor contg. a H2 or a H2/O2 mixt. For the latter, XPS (XPS) expts. show an increased presence of oxygen at the (sub)-surface. Contrary to pure H2-plasma treated samples, H2/O2-treated layers still posses enough cond. to enable STS (Scanning Tunneling Spectroscopy) investigations to be carried out after an annealing at 410 DegC in UHV (Ultra High Vacuum). Evidence for surface resonance states is detected, yielding a possible explanation for the measured cond. UPS (UPS) data point to a neg. electron affinity of -0.3 eV for the H2/O2-treated layers. [on SciFinder (R)

The role of (sub)-surface oxygen on the surface electronic structure of hydrogen terminated (100) CVD diamond

In this work, scanning tunnelling microscopy (STM) and scanning tunnelling spectroscopy (STS) were applied to investigate the surface morphol. and the surface electronic structure of plasma-treated (100)-oriented CVD diamond films. These films were hydrogenated using a conventional MWPE-CVD (microwave plasma enhanced chem. vapor deposition) reactor contg. a H2 or a H2/O2 mixt. A comparison is made between (100)-oriented CVD diamond films hydrogenated with and without a small addn. of oxygen (1%). XPS and UPS (UPS) measurements point to the presence of O-atoms at the (sub)-surface of the diamond film. The measured cond. is significantly different for the two processes of hydrogenation. Annealing expts. point out that the samples, which were terminated using the H2/O2 mixt. are still conductive enough after annealing at 410 DegC to enable STM expts. Here, we discuss the mechanism for STM imaging of H2/O2 treated diamond films, assocd. with surface states induced by the oxygen incorporation. [on SciFinder (R)

Design of a Lab-On-Chip Cartridge for the Optical Detection of Small Molecules based on Dye-Displacement MIPs

Molecular Imprinted Polymers (MIPs) are well known for their specific recognition of a wide variety of different analytes. However, the complex immobilization process of MIPs onto sensor electrodes poses a significant challenge. This research introduces a novel approach to enhance the application potential of MIPs by exploiting dye-displacement MIPs. These synthetic receptors can selectively release dye upon exposure to an aqueous target. A disposable and low-cost lab-on-chip cartridge is presented, enabling the MIPs to interact with the target solution for dye displacement. Furthermore, these cartridges are coupled to a portable optical sensor setup that can be used for screening samples in a user-friendly and fast manner. Characterization experiments demonstrate the capability of the spectrometer setup to identify different color dyes and intensities. Finally, a proof-of-application shows the use of our sensing setup for the indirect detection of 2-methoxphenidine (2-MXP) using dye-loaded MIPs, employing a dose-response characterization (4PL). Furthermore, as the dye displacement and sensing principle are universal, this setup holds promise for various other sensing applications, including food quality assessment, environmental testing, and pharmaceutical analysis