APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

17 Oct 2005

Volume 87, Issue 16, Articles (16xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 87, 161907 (2005); http://dx.doi.org/10.1063/1.2105998 (3 pages)

J. Das, K. B. Kim, F. Baier, W. Löser, and J. Eckert
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Room-temperature hydrogen gas sensor

Farshid Raissi and Rashid Farivar

Appl. Phys. Lett. 87, 164101 (2005); http://dx.doi.org/10.1063/1.2077865 (3 pages) | Cited 8 times

Online Publication Date: 11 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The hydrogen gas sensing ability of n-type PtSi/porous Si Schottky junctions is investigated at room temperature. These junctions exhibit a breakdown-type current-voltage curve, whose breakdown voltage depends on the gas content inside the pores. Hydrogen replaces gases with an inherent dipole moment and increases the breakdown voltage. The response time is very fast, around 6 s, and the recovery time is about 60 s. Concentrations as low as 10 ppm have been detected in the presence of methanol and acetone. Detection has been tested at different temperatures ranging from 273 to 300 K.
Show PACS
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
73.30.+y Surface double layers, Schottky barriers, and work functions

Electrostatic potential in manganite-based heterojunctions by electron holography

H. F. Tian, J. R. Sun, H. B. Lü, K. J. Jin, H. X. Yang, H. C. Yu, and J. Q. Li

Appl. Phys. Lett. 87, 164102 (2005); http://dx.doi.org/10.1063/1.2084344 (3 pages) | Cited 8 times

Online Publication Date: 13 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electric potentials at the manganite-based heterojunctions, composed of La0.9Sr0.1MnO3 and 0.01 wt % Nb-doped SrTiO3 (p-n junction) and La0.7Ce0.3MnO3 and 0.5 wt % Nb-doped SrTiO3 (n-n junction), have been studied by means of off-axis electron holography. The experimental measurements demonstrate that evident electron diffusion from the n-type SrNbxTi1−xO3 to the manganite films occurs in both p-n and n-n heterojunctions. The p-n heterojunction shows a complex potential change across the interface due to the variation of dielectric constant and electronic structure. In situ cooling experimental measurement on n-n junctions reveals an apparent change of potential along with the ferromagnetic phase transition.
Show PACS
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
77.22.Ch Permittivity (dielectric function)
71.20.Ps Other inorganic compounds
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Dd Nonmetallic ferromagnetic materials
68.35.Fx Diffusion; interface formation

Direct measurements of water adsorption enthalpy on hafnia and zirconia

Sergey V. Ushakov and Alexandra Navrotsky

Appl. Phys. Lett. 87, 164103 (2005); http://dx.doi.org/10.1063/1.2108113 (3 pages) | Cited 28 times

Online Publication Date: 14 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A commercial surface area analyzer and Calvet-type microcalorimeter were combined for measurements of heats of gas–solid interactions, providing enhanced resolution, flexibility, and throughput compared to conventional methods. Integral adsorption enthalpies for half monolayer coverage on HfO2 and ZrO2 surfaces were found to be in the range −130–190 and −110–170 kJ per mole of gaseous H2O for differently prepared monoclinic phases and −70 and −90 kJ/mole for tetragonal phases from precipitation. The surface enthalpy for anhydrous tetragonal ZrO2 was derived as 1.23±0.04 J/m2 from water adsorption and high-temperature solution calorimetry data.
Show PACS
65.40.G- Other thermodynamical quantities
68.43.Mn Adsorption kinetics
64.75.-g Phase equilibria
81.30.Mh Solid-phase precipitation

Optical fabrication of three-dimensional polymeric microstructures

Chao-Min Cheng, Bin Li, and Philip R. LeDuc

Appl. Phys. Lett. 87, 164104 (2005); http://dx.doi.org/10.1063/1.2108114 (3 pages) | Cited 2 times

Online Publication Date: 14 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a technique for building three-dimensional structures using optical methods combined with photocuring chemistry. This method merges an optics-based approach with chemical restructuring through the transition of materials from distinct phases. By activating this photocurable material in combination with controlling the intensity distributions that are inherently in optical patterns, in situ fabrication of three-dimensional polymeric microstructures is demonstrated. This experimentally simple approach combined with thermal control can create complex shapes including curved and asymmetric profiles. This method has potential applications in a variety of fields including optical techniques, photoactivatable materials, and laboratory-on-a-chip systems.
Show PACS
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
42.82.Cr Fabrication techniques; lithography, pattern transfer
42.70.Jk Polymers and organics
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close