Use of thermal energy for surface contact potential gas detection

1991 ◽  
Vol 69 (2) ◽  
pp. 1102-1103 ◽  
Author(s):  
A. Balasubramanian ◽  
J. J. Santiago‐Aviles ◽  
Jay N. Zemel
Keyword(s):  
Thermal Energy ◽  
Gas Detection ◽  
Contact Potential ◽  
Surface Contact ◽  
Surface Contact Potential

Manipulation of Surface Charge on GaN

2009 ◽  
Vol 1202 ◽  
Author(s):  
Josephus D. Ferguson ◽  
Michael A. Foussekis ◽  
Monika D. Ruchala ◽  
J. C. Moore ◽  
Michael A. Reshchikov ◽  
...  
Keyword(s):  
Surface Charge ◽  
Surface Potential ◽  
Uv Exposure ◽  
Semiconductor Surface ◽  
Time Behavior ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Uv Illumination ◽  
Surface Contact ◽  
Surface Contact Potential

AbstractWe have characterized the surface charge on a variety of GaN samples using two surface potential techniques, conventional Kelvin probe and scanning Kelvin probe microscope (SKPM). Kelvin probe was primarily used to measure the change in surface potential under UV illumination, otherwise known as the surface photovoltage (SPV). Due to band bending near the semiconductor surface of about 1 eV in dark conditions, the SPV signal for n-type GaN typically reaches 0.5 to 0.6 eV upon switching on UV light. This value can slowly decrease by up to 0.3 eV during UV illumination in air ambient for 2-3 hours. We report that samples with many hours of ambient UV exposure do not show this slow decrease during SPV measurements, consistent with the UV-induced growth of a thicker surface oxide that limits charge transfer. In addition to prolonged UV exposure, the surface contact potential was also manipulated by local charge injection. In this procedure, the surface is charged using a metallized atomic force microscope tip which is scanned in contact with the sample. Subsequent SKPM measurements indicate an increase or decrease in the surface contact potential for the charged region, depending on the applied voltage polarity. Measurements of the discharge behavior in dark for these regions show a logarithmic time behavior, similar to the decay behavior during our observations of SPV transients after switching off the light. As expected, illumination of the surface increases the discharge rate and restores the charged area to its original state.

scholarly journals Effect of surface contact potential in atomic-size contacts

2015 ◽  
Vol 379 (37) ◽  
pp. 2239-2244 ◽  
Author(s):  
C. Rackson ◽  
A. Watt ◽  
W.J. Kim
Keyword(s):  
Contact Potential ◽  
Atomic Size ◽  
Surface Contact ◽  
Surface Contact Potential ◽  
Effect Of Surface

scholarly journals Surface contact potential patches and Casimir force measurements

2010 ◽  
Vol 81 (2) ◽  
Author(s):  
W. J. Kim ◽  
A. O. Sushkov ◽  
D. A. R. Dalvit ◽  
S. K. Lamoreaux
Keyword(s):  
Casimir Force ◽  
Force Measurements ◽  
Contact Potential ◽  
Surface Contact ◽  
Surface Contact Potential

Thermal energy harvesting near-infrared radiation and accessing low temperatures with plasmonic sensors

Nanoscale ◽  
2015 ◽  
Vol 7 (42) ◽  
pp. 17798-17804 ◽  
Author(s):  
Nicholas A. Karker ◽  
Gnanaprakash Dharmalingam ◽  
Michael A. Carpenter
Keyword(s):  
Energy Harvesting ◽  
Thermal Energy ◽  
Gold Nanorods ◽  
Low Temperatures ◽  
Near Infrared ◽  
Gas Detection ◽  
Near Infrared Radiation ◽  
Plasmonic Sensors ◽  
Thermal Energy Harvesting ◽  
Ppm Level

Near-infrared (NIR) thermal energy harvesting has been demonstrated for gold nanorods (AuNRs), allowing concentration dependent, ppm-level, gas detection of H2, CO, and NO2at 500 °C without using a white light source.

Study of Surface Defects in 4H-SiC Schottky Diodes Using a Scanning Kelvin Probe

2013 ◽  
Vol 740-742 ◽  
pp. 677-680
Author(s):  
J. Mizsei ◽  
O. Korolkov ◽  
J. Toompuu ◽  
V. Mikli ◽  
T. Rang
Keyword(s):  
Surface Defects ◽  
Schottky Diodes ◽  
Critical Role ◽  
Contact Potential Difference ◽  
Kelvin Probe ◽  
Leakage Currents ◽  
Contact Potential ◽  
Scanning Kelvin Probe ◽  
Surface Contact Potential ◽  
Kelvin Probe Method

Abstract. In the present paper we attempt to study and explain the increased leakage currents in Schottky diodes with an integrated p-n-structure. By a scanning Kelvin probe method (vibrating capacitor) were obtained the local variations of surface contact potential difference (CPD) for the chips with large and small leakage currents. It is shown that samples with higher leakage currents have smaller surface potential barrier. The SEM investigations revealed that a critical role in increasing leakage currents play the dislocations penetrating from the substrate into the epitaxial layer.

A Modified Thromboplastin Screening Test

1961 ◽  
Vol 06 (03) ◽  
pp. 492-497 ◽  
Author(s):  
Janet C. Macpherson ◽  
R. M Hardisty
Keyword(s):  
Standard Method ◽  
Comparative Studies ◽  
Screening Test ◽  
Incubation Mixture ◽  
Surface Contact ◽  
Modified Test ◽  
Effect Of Surface

SummaryA modification of the thromboplastin screening test of Hicks and Pitney is described, in which the effect of surface contact on the test plasma is controlled by the addition of a suspension of kaolin to the incubation mixture before recalcification.Comparative studies show the modified test to give more reproducible results than the standard method.

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