Influence of crystallite-boundary potential barriers on the thermopower and peltier effect in polycrystalline ferroelectric semiconductors

2006 ◽  
Vol 48 (10) ◽  
pp. 1924-1928
Author(s):  
A. N. Pavlov ◽  
I. P. Raevsky ◽  
V. P. Sakhnenko ◽  
S. A. Kuropatkina ◽  
S. I. Raevskaya
Keyword(s):  
Peltier Effect ◽  
Potential Barriers ◽  
Boundary Potential ◽  
Crystallite Boundary

scholarly journals Nanoscale Tuning of Grain Boundary Potential Barriers in Doped Strontium Titanate

2003 ◽  
Vol 9 (S02) ◽  
pp. 672-673
Author(s):  
Pradyumna L. Prabhumirashi ◽  
Andrew R. Lupini ◽  
Stephen J. Pennycook ◽  
Vinayak P. Dravid
Keyword(s):  
Grain Boundary ◽  
Strontium Titanate ◽  
Potential Barriers ◽  
Boundary Potential

Models for Electronic Conduction Across Ceramic Grain Boundaries

1985 ◽  
Vol 60 ◽  
Author(s):  
L. C. Burton
Keyword(s):  
Grain Boundary ◽  
Space Charge ◽  
Boundary Behavior ◽  
High Resistivity ◽  
Potential Barriers ◽  
Ohmic Behavior ◽  
Boundary Potential ◽  
Electronic Current ◽  
Grain Width ◽  
Limited Diffusion

AbstractElectronic current flow over grain boundary potential barriers for low resistance grains is first reviewed. It is then shown that if the resistance of the grains increases and/or grain size is reduced, the grains may be totally depleted of mobile charge. The grain boundary barrier is thus reduced to (D/2W)2 of its original large grain value, D being grain width and W the full space charge width. For high resistivity grains satisfying the relation D ≪ 2W, the conduction band becomes essentially flat. Phenomena formerly caused by grain boundary potential barriers (varistor and PTC effects seen in semiconducting ceramic) will be greatly reduced, or eliminated.Commercial COG and X7R MLC capacitors exhibit a transition from super-ohmic to ohmic behavior at high voltages, paralleling the behavior of the varistor. Two possible mechanisms that could account for this are varistor-like grain boundary behavior, or space charge limited diffusion current.

scholarly journals Carrier Transport in Ultra-Thin Nano/Polycrystalline Silicon Films and Nanowires

2001 ◽  
Vol 664 ◽  
Author(s):  
Toshio Kamiya ◽  
Yong T. Tan ◽  
Yoshikazu Furuta ◽  
Hiroshi Mizuta ◽  
Zahid A.K. Durrania ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Polycrystalline Silicon ◽  
Carrier Transport ◽  
Crystalline Silicon ◽  
Thermionic Emission ◽  
Nanocrystalline Silicon ◽  
Silicon Films ◽  
Si Nanowires ◽  
Potential Barriers ◽  
Boundary Potential

ABSTRACTCarrier transport was investigated in two different types of ultra-thin silicon films, polycrystalline silicon (poly-Si) films with large grains > 20 nm in size and hydrogenated nanocrystalline silicon (nc-Si:H) films with grains 4 nm – 8 nm in size. It was found that there were local non-uniformities in grain boundary potential barriers in both types of films. Single-electron charging effects were observed in 30 nm × 30 nm nanowires fabricated in 30 nm-thick nc-Si:H films, where the electrons were confined in crystalline silicon grains encapsulated by amorphous silicon. In contrast, the poly-Si nanowires of similar dimensions showed thermionic emission over the grain boundary potential barriers formed by carrier trapping in grain boundary defects.

Patient feedback on a new method of consulting with the GP; an analysis of responses by users of online triage software

2018 ◽  
Vol 68 (suppl 1) ◽  
pp. bjgp18X696773
Author(s):  
Abi Eccles ◽  
Mike Hopper ◽  
Helen Atherton
Keyword(s):  
Free Text ◽  
Telephone Consultation ◽  
Face To Face ◽  
Potential Barriers ◽  
Online Consultation ◽  
Patient Feedback ◽  
Levels Of Use ◽  
Negative Perceptions ◽  
Context Dependent ◽  
Feedback Data

BackgroundOnline triage software is a new way to triage patients online that allows patients to describe their problem via an online form. A GP then contacts the patient to arrange either a face-to-face or telephone consultation.AimThis study aimed to explore use of online consultation software and gain insight into patients’ experiences of using online consultations, identifying potential barriers and facilitators to use.MethodThis is a mixed methods retrospective study analysing data about patient users and their associated feedback. Data from a sample of 5591 patients were quantitatively analysed to describe characteristics of users. 576 out of the 5591 users left free-text feedback comments on their experience of use. These were thematically analysed.ResultsThe highest levels of use were observed in 25–35-year olds and lowest from those aged >65. Key themes identified included convenience, consultation quality, appropriateness, resource-use and functionality. Within each, a range of subthemes were present representing both positive and negative perceptions, suggesting that experiences of using online triage varied and were often context-dependentConclusionThere are various advantages to online triage software, but these are context-dependent. Therefore, such applications should be offered as an additional way to contact the GP surgery, rather than a replacement for more established methods, to ensure appropriate and equal access for patients.

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