This letter reports the synthesis of indium nitride (InN) nanowires on gold-patterned silicon substrates in a controlled manner using a method involving thermal evaporation of pure indium. The locations of these InN nanowires were controlled by depositing gold in desired areas on the substrates. Scanning electron microscopy and transmission electron microscopy investigations showed that the InN nanowires are single crystals with diameters ranging from 40 to 80 nm, and lengths up to 5 μm. Energy dispersive x-ray spectrometry showed that the ends of the nanowires are composed primarily of Au, and the rest of the nanowires were InN with no detectable Au incorporations. The Raman spectra showed peaks at 445, 489, and 579 cm−1, which are attributed to the A1(transverse optical), E2, and A1(longitudinal optical) phonon modes of the wurtzite InN structure, respectively. Photoluminescence spectra of the InN nanowires showed a strong broad emission peak at 1.85 eV.

A new method is described for conductive silver film formation. An inkjet printing device with two ink channels was used to deposit silver thin films. Two inks, silver ammonia and formaldehyde solutions, were separately ejected, mixed, and reacted on glass slides. The so-called silver mirror reaction created smooth and continuous silver lines of 90 micron in width with an average film thickness of 200 nm. Surface profilometry was used to measure the thicknesses and cross section areas of printed silver lines. The electrical conductivity of the resulting silver lines is 6% of bulk silver at room temperature. After sintering at 150 C for an hour, electrical conductivity was enhanced to 14%. Scanning electron microscopy (SEM) showed that the microstructure of the printed thin films consists of nanoparticle grains of 50 to 200 nanometres. Results of X-ray diffraction (XRD) and Energy-dispersive X-ray spectroscopy (EDS) further confirmed our printed films purely comprised of face-centered cubic (FCC) silver crystalline. The printed conductive lines could be used for various applications, such as embedded printed circuit boards, micro-electromechanical systems (MEMS), and radio frequency identification (RFID) tags.

No abstract

We report the structure and emission properties of ternary (In,Ga)N nanowires (NWs) embedded with self‐assembled quantum dots (SAQDs). InGaN NWs are fabricated by the reaction of In, Ga and NH3 via a vapor–liquid–solid (VLS) mechanism, using Au as the catalyst. By simply varying the growth temperature, In‐rich or Ga‐rich ternary NWs have been produced. X‐ray diffraction, Raman studies and transmission electron microscopy reveal a phase‐separated microstructure wherein the isovalent heteroatoms are self‐aggregated, forming SAQDs embedded in NWs. The SAQDs are observed to dominate the emission behavior of both In‐rich and Ga‐rich NWs. Temperature‐dependent photoluminescence (PL) measurements indicate relaxation of excited electrons from the matrix of the Ga‐rich NWs to their embedded SAQDs. A multi‐level band schema is proposed for the case of In‐rich NWs, which showed an anomalous enhancement in the PL peak intensity with increasing temperature accompanies with red shift in its peak position.

Alumina ceramics were brazed to Inconel 600 and UMCo-50 superalloys at 900 °C for 10 min using an Sn10Ag4Ti active filler metal. The brazing filler showed good wettability on alumina and superalloys. The flexural strengths were 69 and 57 MPa for alumina/Inconel 600 and alumina/UMCo-50 joints, respectively. In both cases, the brazed specimens fractured along the Sn10Ag4Ti/superalloy interfaces after four-point bending tests. Electron probe microanalysis (EPMA) elemental mapping revealed that the Ni of Inconel 600 and the Co of UMCo-50 dissolved into Sn10Ag4Ti filler metal, which serves to reinforce the weak Sn10Ag4Ti matrix.