Photoelectrocatalytic reduction of carbon dioxide to methanol at cuprous oxide foam cathode

Photoelectrocatalytic performance of Cu₂O foam electrodes for reduction of CO₂ to methanol depends largely on exposed Cu₂O{111} facets.

High-temperature X-ray diffraction and thermal expansion of nanocrystalline and coarse-crystalline acanthite α-Ag2S and argentite β-Ag2S

An in situ study of thermal expansion of polymorphic phases of coarse-crystalline and nanocrystalline silver sulfide – monoclinic acanthite α-Ag₂S and cubic argentite β-Ag₂S – has been carried out for the first time using the high-temperature X-ray diffraction method.

An in situ high-temperature scanning electron microscopy study of acanthite–argentite phase transformation in nanocrystalline silver sulfide powder

In situ SEM observation of the transformation “acanthite–argentite” which occurs in nanocrystalline and coarse-crystalline silver sulfide at ∼450 K is performed.

Crystallization of Electrodeposited Germanium Thin Film on Silicon (100)

We report the crystallization of electrodeposited germanium (Ge) thin films on n-silicon (Si) (100) by rapid melting process. The electrodeposition was carried out in germanium (IV) chloride: propylene glycol (GeCl₄:C₃H₈O₂) electrolyte with constant current of 50 mA for 30 min. The measured Raman spectra and electron backscattering diffraction (EBSD) images show that the as-deposited Ge thin film was amorphous. The crystallization of deposited Ge was achieved by rapid thermal annealing (RTA) at 980 °C for 1 s. The EBSD images confirm that the orientations of the annealed Ge are similar to that of the Si substrate. The highly intense peak of Raman spectra at 300 cm⁻¹ corresponding to Ge-Ge vibration mode was observed, indicating good crystal quality of Ge. An additional sub peak near to 390 cm⁻¹ corresponding to the Si-Ge vibration mode was also observed, indicating the Ge-Si mixing at Ge/Si interface. Auger electron spectroscopy (AES) reveals that the intermixing depth was around 60 nm. The calculated Si fraction from Raman spectra was found to be in good agreement with the value estimated from Ge-Si equilibrium phase diagram. The proposed technique is expected to be an effective way to crystallize Ge films for various device applications as well as to create strain at the Ge-Si interface for enhancement of mobility.

New real-time analytical applications of electrochemical quartz crystal microbalance Stoichiometry and phase composition monitoring of electrodeposited thin chalcogenide films

The electrochemical quartz crystal microbalance (EQCM) has recently gained increasing popularity as a powerful tool for electrochemical interface examinations. This paper reports on its great potential for developing new real-time analytical protocols. Potentiostatic coulometry is used in conjunction with quartz crystal microgravimetry (QCMg) with controlled hydrodynamics to develop two new analytical procedures: real-time stoichiometry monitoring of electrodeposited binary chalcogenide films and phase composition quantification of electrodeposited ternary chalcogenide compounds. The newly developed EQCM methods are illustrated on the examples of Ag2+deltaSe-electrodeposited films and the electroformation of ternary CuAgSe-films. Both compounds have been successfully used as ion-selective membranes for flow-injection detectors. The experimental set-up including hydrodynamic control, the main strategy of the approach used and its scope and limitations are broadly discussed. The obtained data allow for real time profile monitoring of either stoichiometry (Ag2+deltaSe-case) or phase composition (CuAgSe-case).