1/f NOISE DUE TO THE RETURN STATISTICS OF MOBILE POINT DEFECTS IN EXTRINSIC SEMICONDUCTOR MATERIALS

2007 ◽  
Vol 07 (01) ◽  
pp. C1-C18 ◽  
Author(s):  
FERDINAND GRÜNEIS
Keyword(s):  
Point Defects ◽  
Power Law ◽  
Charge Carriers ◽  
Recombination Process ◽  
Semiconductor Materials ◽  
Bohr Radius ◽  
Mobile Defect ◽  
The Times ◽  
At Will

We investigate fixed dopants in the presence of mobile point defects like foreign atoms or vacancies. A mobile defect entering the first Bohr radius RB of a dopant will modulate the generation-recombination process. The times a defect walks inside or outside RB are shown to be power-law distributed giving rise to 1 / fb noise. The predicted Hooge coefficient αdef depends on RB, on the normalized fluctuations of charge carriers and on the number of charge carriers compared to lattice sites; our model suggests that the magnitude of 1/ f noise can be decreased at will by increasing the ionization of dopants.

1/f NOISE IN EXTRINSIC SEMICONDUCTOR MATERIALS INTERPRETED AS MODULATED GENERATION-RECOMBINATION NOISE

2010 ◽  
Vol 09 (02) ◽  
pp. 229-243 ◽  
Author(s):  
FERDINAND GRÜNEIS
Keyword(s):  
Point Defects ◽  
Power Law ◽  
Modulation Depth ◽  
Charge Carriers ◽  
Semiconductor Materials ◽  
Bohr Radius ◽  
R Process ◽  
The Times

We investigate fixed dopants in the presence of mobile point defects. A defect entering the first Bohr radius RB of a dopant will modulate the generation-recombination (g-r) process. The times a defect walks inside and outside of RB are found to be power-law distributed; correspondingly, the modulated g-r process exhibits 1/fb noise. The predicted Hooge coefficient depends on RB, on the normalized fluctuations of charge carriers, the number of lattice sites and on the modulation depth of the g-r process.

An Intermittent Generation–Recombination Process as a Possible Origin of 1/f Fluctuations in Semiconductor Materials

2017 ◽  
Vol 16 (04) ◽  
pp. 1750034 ◽  
Author(s):  
Ferdinand Grüneis
Keyword(s):  
Quantum Dots ◽  
Temperature Dependence ◽  
Power Law ◽  
Phonon Scattering ◽  
Recombination Process ◽  
Semiconductor Materials ◽  
Conduction Electrons ◽  
Fluorescence Intermittency ◽  
The Impact ◽  
Electron Phonon Scattering

Inspired by the phenomenon of fluorescence intermittency in quantum dots and other materials, we introduce small off-states (intermissions) which interrupt the generation and recombination (= [Formula: see text]–[Formula: see text]) process in a semiconductor material. If the remaining on-states are power-law distributed, we find an almost pure 1/[Formula: see text] spectrum. Besides well-known [Formula: see text]–[Formula: see text] noise, we obtain two 1/[Formula: see text] noise components which can be attributed to the intermittent generation and recombination process. These components can be given the form of Hooge's relation with a Hooge coefficient [Formula: see text] describing the contribution of the generation and recombination process, respectively. Herein, the coefficients [Formula: see text] and [Formula: see text] describe impact of intermissions which in general are different for the generation and recombination process. The impact of [Formula: see text]–[Formula: see text] noise on 1/[Formula: see text] noise is comprised in the coefficient [Formula: see text] for the generation and [Formula: see text] for the recombination process. These coefficients are specified for an intrinsic and a slightly extrinsic semiconductor as well as for a semiconductor with traps; for the latter, the temperature dependence of 1/[Formula: see text] noise is also investigated. 1/[Formula: see text] noise is shown to be inversely related to the number of neutral and ionized [Formula: see text]-atoms rather than to the number of conduction electrons as defined in Hooge's relation. As a possible origin of 1/[Formula: see text] noise in semiconductors, electron–phonon scattering is suggested.

scholarly journals Ion Dynamics Study of Potato Starch + Sodium Salts Electrolyte System

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Tuhina Tiwari ◽  
Neelam Srivastava ◽  
P. C. Srivastava
Keyword(s):  
Electrical Properties ◽  
Power Law ◽  
Polymer Electrolytes ◽  
Potato Starch ◽  
Charge Carriers ◽  
Ion Dynamics ◽  
Electrolyte System ◽  
Sodium Salts ◽  
Dielectric Data

The effect of different anions, namely,SCN−,I−, andClO4−, on the electrical properties of starch-based polymer electrolytes has been studied. Anion size and conductivity are having an inverse trend indicating systems to be predominantly anionic conductor. Impact of anion size and multiplet forming tendency is reflected in number of charge carriers and mobility, respectively. Ion dynamics study reveals the presence of different mechanisms in different frequency ranges. Interestingly, superlinear power law (SLPL) is found to be present at <5 MHz frequency, which is further confirmed by dielectric data.

Compensating defect centres in semi-insulating 6H-SiC

2009 ◽  
Vol 17 (1) ◽  
pp. 1-7 ◽  
Author(s):  
P. Kamiński ◽  
R. Kozłowski ◽  
M. Miczuga ◽  
M. Pawłowski ◽  
M. Kozubal ◽  
...  
Keyword(s):  
Point Defects ◽  
Emission Rate ◽  
Thermal Emission ◽  
Charge Compensation ◽  
Charge Carriers ◽  
Two Dimensional ◽  
New Approach ◽  
Temperature Dependences ◽  
Transient Spectroscopy ◽  
Defect Centres

AbstractPhotoinduced transient spectroscopy (PITS) has been applied to study electronic properties of point defects associated with charge compensation in semi-insulating (SI) 6H-SiC substrates. The photocurrent relaxation waveforms were digitally recorded in a wide temperature range of 20–800 K and in order to extract the parameters of defect centres, a two-dimensional analysis of the waveforms as a function of time and temperature has been implemented. As a result, the processes of thermal emission of charge carriers from defect centres were seen on the spectral surface as the folds, whose ridgelines depicted the temperature dependences of emission rate for detected defect centres. The new approach was used to compare the defect levels in vanadium-doped and vanadium-free (undoped) SI 6H-SiC wafers.

AgBr tetradecahedrons with co-exposed {100} and {111} facets: simple fabrication and enhancing spatial charge separation using facet heterojunctions

2016 ◽  
Vol 4 (47) ◽  
pp. 18570-18577 ◽  
Author(s):  
Shenyuan Bao ◽  
Zhiqiang Wang ◽  
Xueqing Gong ◽  
Cuiyun Zeng ◽  
Qiangfang Wu ◽  
...  
Keyword(s):  
Solar Energy ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Charge Separation ◽  
Energy Conversion Efficiency ◽  
Charge Carriers ◽  
Semiconductor Materials ◽  
Separation Rate ◽  
Spatial Charge ◽  
Solar Energy Conversion Efficiency

The solar energy conversion efficiency of semiconductor materials is closely related to the separation rate of photogenerated charge carriers.

scholarly journals Forecasting Bubble Bursts Assessing the Ex-ante Usability of the Log-Periodic Power Law Singularity Model

2020 ◽  
pp. 30-46
Author(s):  
Marcus Gustavsson ◽  
Daniel Levén ◽  
Professor Hans Sjögren
Keyword(s):  
Financial Markets ◽  
Power Law ◽  
Power Law Model ◽  
Speculative Bubbles ◽  
Oscillatory Pattern ◽  
Ex Ante ◽  
Price Movements ◽  
The Times ◽  
Oscillatory Cycle

Speculative bubbles have throughout the times foiled various scholars; many have tried to accurately predict their ends, but few have succeeded. In this study, we examine the robustness and ex-ante usability of the log-periodic power-law model in predicting end dates of speculative bubbles on one mature and two emerging financial markets. We have found that the predicted end dates are somewhat dependent on at which point in time the prediction is conducted, especially in regards to at which point in the oscillatory cycle the prediction is conducted. This is mostly due to that predictions are sensitive to their most recent price movements, especially when data is limited and a clear oscillatory pattern is not yet established. We conclude that observing one particular estimation without further context can be misleading. To achieve a sound understanding of and reasonable expectations on how prices might develop it is necessary to follow a bubble as it develops. This study is, to our knowledge, first to examine to what extent the predictions of the model are dependent on at which point in time the predictions are conducted.

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