scholarly journals Kinetic photovoltage along semiconductor-water interfaces

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jidong Li ◽  
Yuyang Long ◽  
Zhili Hu ◽  
Jiyuan Niu ◽  
Tiezhu Xu ◽  
...  
Keyword(s):  
Electric Potential ◽  
Silicon Surface ◽  
Photovoltaic Effect ◽  
Potential Gradient ◽  
High Permittivity ◽  
Polar Liquids ◽  
Nonpolar Liquids ◽  
A Charge ◽  
Silicon Based ◽  
Silicon Hydrogel

AbstractExternal photo-stimuli on heterojunctions commonly induce an electric potential gradient across the interface therein, such as photovoltaic effect, giving rise to various present-day technical devices. In contrast, in-plane potential gradient along the interface has been rarely observed. Here we show that scanning a light beam can induce a persistent in-plane photoelectric voltage along, instead of across, silicon-water interfaces. It is attributed to the following movement of a charge packet in the vicinity of the silicon surface, whose formation is driven by the light-induced potential change across the capacitive interface and a high permittivity of water with large polarity. Other polar liquids and hydrogel on silicon also allow the generation of the in-plane photovoltage, which is, however, negligible for nonpolar liquids. Based on the finding, a portable silicon-hydrogel array has been constructed for detecting the shadow path of a moving Cubaris. Our study opens a window for silicon-based photoelectronics through introducing semiconductor-water interfaces.

Removal of heavy metal from soil and groundwater by in-situ electrokinetic remediation

2000 ◽  
Vol 42 (7-8) ◽  
pp. 335-343 ◽  
Author(s):  
S. Shiba ◽  
S. Hino ◽  
Y. Hirata ◽  
T. Seno
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Electric Potential ◽  
Potential Gradient ◽  
Electrokinetic Remediation ◽  
Contaminated Aquifer ◽  
Physico Chemical ◽  
Operational Variables ◽  
Mass Transport Process

The operational variables of electrokinetic remediation have not been cleared yet, because this method is relatively new and is an innovative technique in the aquifer remediation. In order to investigate the operational variables of the electrokinetic remediation, a mathematical model has been constructed based on the physico chemical mass transport process of heavy metals in pore water of contaminated aquifer. The transport of the heavy metals is driven not only by the hydraulic flow due to the injection of the purge water but also by the electromigration due to the application of the electric potential gradient. The electric potential between anode and cathode is the important operational variable for the electrokinetic remediation. From the numerical simulations with use of this model it is confirmed that the remediation starts from the up stream anode and gradually the heavy metal is transported to the down stream cathode and drawn out through the purge water.

Photovoltaic and Electroluminescent Properties of Stainetched Porous Silicon Based Heterojunctions

1995 ◽  
Vol 405 ◽  
Author(s):  
D. Dimova-Malinovska ◽  
M. Tzolov ◽  
M. Kamenova ◽  
N. Tzenov ◽  
M. Sendova-Vassileva ◽  
...  
Keyword(s):  
Light Emission ◽  
Photovoltaic Effect ◽  
Luminescent Properties ◽  
Porous Si ◽  
Photoelectric Properties ◽  
Type C ◽  
P Type ◽  
Silicon Based ◽  
Electrical Bias ◽  
Stain Etching

AbstractThe results of photoelectric properties and electroluminescent studies of structures ZnO/porous Si/p-type c-Si/Al and ZnO/porous Si/p-n c-Si junction/Al are presented. Porous Si is prepared by stain etching of c-Si covered with thin Al film. The transparent ZnO film allows light emission through the top surface of the device under forward electrical bias. Photocurrent is observed under reverse bias and a photovoltaic effect is measured on the p-n junction PS device. The model based on injection of minority carriers through a narrow energy barrier into the porous Si and the presence of the barrier at the interface porous Si/c-Si is suggested for describing the electrical, photoelectric and luminescent properties of the structures.

Photovoltaic Characterization of Trapping in Porous Silicon

1994 ◽  
Vol 358 ◽  
Author(s):  
D. W. Boeringer ◽  
R. Tsu
Keyword(s):  
Porous Silicon ◽  
Photovoltaic Effect ◽  
Light Spot ◽  
Dangling Bond ◽  
Photogenerated Electrons ◽  
Device Applications ◽  
Photovoltaic Characterization ◽  
P Type ◽  
Silicon Based ◽  
Position Sensitive Detectors

ABSTRACTWe report the first observation of the lateral photovoltaic effect in porous silicon. Contacts placed on either side of a porous silicon region develop a voltage up to several millivolts if the sample is asymmetrically illuminated. If the light spot is closer to one contact, the voltage will have one polarity; if it is closer to the other contact, the polarity will be opposite. In the case of n-type, the contact nearest the light spot is positive; for p-type, the contact nearest the light spot is negative In the region between the contacts, the photovoltage varies almost linearly with the position of the light spot, over a distance 4.5 cm across. The origin of our lateral photoeffect may be explained by the trapping of photoexcited carriers by a pair of dangling bond centers in porous silicon. In the case of p-type, the photogenerated electrons are trapped by the dangling bond states while holes diffuse away in the substrate. The situation for n-type is opposite; holes are trapped by the dangling bond states while electrons diffuse away in the substrate. This differs from the conventional lateral photoeffect, which arises under the nonuniform illumination of a junction between two layers of differing conductivities. Hamamatsu sells silicon-based position-sensitive detectors with a resolution down to 0.1 µm. The possibility of using this lateral photoeffect to characterize these dangling bond states in porous silicon as well as several possible device applications will be discussed.

scholarly journals Influence of a single lightning discharge on the intensity of an air electric field and acoustic emission of near-surface rocks

Solid Earth ◽  
2012 ◽  
Vol 3 (2) ◽  
pp. 307-311 ◽  
Author(s):  
S. E. Smirnov ◽  
Y. V. Marapulets
Keyword(s):  
Acoustic Emission ◽  
Electric Field ◽  
Normal Level ◽  
Electric Potential ◽  
Characteristic Time ◽  
Lightning Discharge ◽  
Potential Gradient ◽  
Capacitor Discharge ◽  
Near Surface ◽  
Sharp Fall

Abstract. The effect was observed as a sharp fall of the electric potential gradient from +80 V m−1 down to –21 V m−1. After that the field returned to its normal level according to the formula of the capacitor discharge with 17 s characteristic time. Simultaneously, the response of the acoustic emission of surface rocks in the range of frequencies between 6.5 kHz and 11 kHz was evaluated.

scholarly journals Silicon-based Biosensors for Rapid Detection of Protein or Nucleic Acid Targets

2001 ◽  
Vol 47 (10) ◽  
pp. 1894-1900 ◽  
Author(s):  
Robert Jenison ◽  
Helen La ◽  
Ayla Haeberli ◽  
Rachel Ostroff ◽  
Barry Polisky
Keyword(s):  
Thin Film ◽  
Nucleic Acid ◽  
Interferon Γ ◽  
Wild Type ◽  
Signal To Noise ◽  
Cytokine Detection ◽  
Apparent Color ◽  
Multianalyte Detection ◽  
A Charge ◽  
Silicon Based

Abstract Background: We developed a silicon-based biosensor that generates visual, qualitative results or quantitative results for the detection of protein or nucleic acid targets in a multiplex format. Methods: Capture probes were immobilized either passively or covalently on the optically coated surface of the biosensor. Intermolecular interactions of the immobilized capture probe with specific target molecules were transduced into a molecular thin film. Thin films were generated by enzyme-catalyzed deposition in the vicinity of the surface-bound target. The increased thickness on the surface changed the apparent color of the biosensor by altering the interference pattern of reflected light. Results: Cytokine detection was achieved in a 40-min multiplex assay. Detection limits were 4 ng/L for interleukin (IL)-6, 31 ng/L for IL1-β, and 437 ng/L for interferon-γ. In multianalyte experiments, cytokines were specifically detected with signal-to-noise ratios ranging from 15 to 80. With a modified optical surface, specificity was also demonstrated in a nucleic acid array with unambiguous discrimination of single-base changes in a 15-min assay. For homozygous wild-type and homozygous mutant samples, signal-to-noise ratios of ∼100 were observed. Heterozygous samples yielded approximately equivalent signals for wild-type and mutant capture probes. Conclusions: The thin-film biosensor allows rapid, sensitive, and specific detection of protein or nucleic acid targets in an array format with results read visually or quantified with a charge-coupled device camera. This biosensor is suited for multianalyte detection in clinical diagnostic assays.

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