9 research outputs found

    Thermodynamic Properties of Methanol in the Critical and Supercritical Regions

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    Bispectrum of the 1/F noise in diodes on quantum dots and wells

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    The bispectrum of the 1/f noise is investigated in the present work. For the Gaussian noise it equals zero. LEDs on self-organized InAs/GaAs quantum dots and laser diodes on In0.2Ga0.8As/GaAs/InGaP quantum wells made in Russia were tested. The voltage noise was analyzed in a wide interval of currents through the diodes. Estimates of the probability density function and semi-invariants of the noise have not revealed any appreciable deviations from the Gauss law. Noise spectra Sv(f)in the range 1 Hz - 20 kHz were analyzed. In most cases the frequency exponent γs of the spectrum is close to one, the Hooge’s parameter αH has magnitude of the order 10-4. The bispectrum Bv(f1,f2of the noise is a complex function of frequencies f1 and f2. Its absolute value is decreasing while moving from the beginning of the frequency plane Of1f2. The decrease along the bisector (f1 = f2 = f) follows the power law characterized by the frequency exponent γB ≈ 1.5 γs. The dependence of the "height" of |Bv(f,f)| on the current through the diode is qualitatively similar to this one for the spectrum. The power law describes these dependences, however the exponents are essentially different

    Difference in dependence of 1/f and RTS noise on current in quantum dots light emitting diodes

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    Low frequency noise characteristics of light-emitting diodes with InAs quantum dots in GaInAs layer are investigated. Two noise components were found in experimental noise records: RTS, caused by burst noise, and 1/f Gaussian noise. Extraction of burst noise component from Gaussian noise background was performed using standard signal detection theory and advanced signal-processing techniques. It was found that Hooge's empirical relation applied to diodes by Kleinpenning is applicable to the electric 1/f noise of quantum dot diodes as well. Two different spectra decomposition techniques are used to obtain burst noise spectra. Bias dependences of burst and 1/f noise are compared. It is concluded that the RTS noise and 1/f noise have different physical origins in light-emitting diodes with quantum dots
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