Ambipolar diffusion noise in a semiconductor in the presence of a magnetic field

• Published in: Journal of applied physics 1972-01, Vol.43 (8), p.3571-3575
• Main Authors: Maldonado, C.D., Ayala, I.L., Bhattacharjie, A.
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.1661757

The noise spectrum due to fluctuations of electron-hole pairs in a semiconductor in the presence of a magnetic field when ambipolar drift and generation recombination are the only important noise processes was presented in a previous paper. In this paper the noise spectrum is presented for the opposite case when ambipolar diffusion and generation recombination are the important processes with ambipolar drift being negligible and unimportant. This spectrum was obtained via the Green's function for the macroscopic differential equation which governs the behavior of the conditional average for fluctuations in the electron-hole-pair particle density when ambipolar diffusion and generation recombination are the only important noise processes. From the obtained result for the spectrum, numerical calculations were carried out in order to display the functional dependence of the noise spectrum on frequency and magnetic field strength for fixed ratios of the mean volume lifetime of electron-hole pairs to the characteristic ambipolar diffusion time of electron-hole pairs along the direction of the magnetic field. Finally, it is shown that for high frequencies the asymptotic dependence of the spectrum on frequency obeys the ``universal 3/2 power law''.