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1/f Noise by Quantum Mechanics

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1 1/f Noise by Quantum Mechanics
Thomas Prevenslik QED Radiations Discovery Bay, Hong Kong Enter speaker notes here. 1 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

2 In 1925, Johnson and Nyquist found vacuum tubes emitted white noise.
Introduction In 1925, Johnson and Nyquist found vacuum tubes emitted white noise. White noise has a constant power spectrum from thermal agitation of charges inside a resistor without applied voltage. 1/f noise differs. Under applied voltage the frequency f of the power spectrum increases as f is lowered, i.e., having a slope of -1 on a log-log plot of noise vs. frequency. 2 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

3 Propose mechanism for 1/f noise in nanoelectronics
Background Generally, 1/f theories avoid the physical mechanism with emphasis placed on mathematical explanations of how /f noise may occur. Propose mechanism for 1/f noise in nanoelectronics  Purpose 3 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

4 Hooge Relation 4 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

5 Problem The residence time of the electron in the size of the sample. In a 1 cm sample, an electron resides < 0.1 s. Low frequency 1/f noise requires residence >> 1 s. Nanoelectronics are far more restrictive Electrons are not the source of 1/f noise in Nanoelectronics 5 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

6 QED = Quantum electrodynamics
Hypothesis 1/f noise in nanoelectronics is a QM effect that conserves Joule heat by creating QED photons that produce charge by the photoelectric effect. QM = Quantum Mechanics QED = Quantum electrodynamics 6 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

7 Heat Capacity of the Atom
Classical Physics (kT > 0) kT eV QM (kT = 0) Nanostructures In nanostructures, QM requires atoms to have zero heat capacity 7 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

8 Conservation of Energy
Lack of heat capacity by QM precludes conservation of Joule heat in nanoelectroncs by an increase in temperature, but how does conservation proceed? Absorbed EM energy is conserved by creating QED photons inside the nanostructure - by frequency up or down - conversion to the TIR resonance of the nanostructure. TIR = Total Internal Reflection 8 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

9 TIR Confinement Since the refractive index of nanoelectroncs is greater than that of the surroundings, the QED photons are confined by TIR Nanostructures ( films, wires) have high surface to volume ratio, but why important? By QM, EM energy absorbed in the surface of nanostructures provides the TIR confinement of the QED photons. QED photons are spontaneously created by Joule heat dissipated in nanoelectronics. Simply, f = c/  = 2nd E = hf For a spherical NP having diameter D,  = 2D 9 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

10 QED Photons and Excitons
QED Photon Rate P = Joule heat E = QED Photon energy  = Absorbed Fraction Exciton Rate Y = Yield of Excitons / QED Photon 10 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

11 Exciton Response 11 Electrons Holes
Where, QE and QH are number electrons and holes, F = Vo/L is the field E and H are electron and hole mobility Electrons Holes The solution 11 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

12 Resistance and Current
 = Conductivity  = Resistivity 12 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

13 Charge Rise Time 13 d = 20 nm and Vo = 1 V Ro = 25 M and P = 1 W
H = m2/ V-s 13 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

14 1/f Noise Mechanism 14 Abrupt change in Charge Step change in Power
Fourier Transform of Step in Power  1/f Noise /2 - /2 X(t) t  14 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

15 Conclusions The mechanism that underlies the 1/f spectra in nanowires is the QED induced conservation of Joule heat by creating charge instead of by increase in temperature. 1/f noise in SnO2 nanowires has nothing to do with a large number of free electrons by Hooge’s theory, but rather on the creation of small numbers ~ 100 holes by the photoelectric effect from QED induced EM radiation. 15 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012

16 Questions & Papers Enter speaker notes here. 16 ICCSS 2012 : Inter.Conf. Circuits, Systems, and Simulations, Hong Kong. Aug. 3-5, 2012


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