Nonlocal effects and transfer fields for electronic noise in small devices

摘要

This paper overviews and implements the transfer-field method applied to the calculation of electronic noise in small semiconductor structures. Two basic schemes are used and developed in detail. The former considers velocity fluctuations and the latter acceleration fluctuations as microcopic noise sources. We show that the latter scheme has several advantages with respect to the former one. Indeed, starting from Markovian noise sources, the latter scheme separates the time and spatial evolution of the local noise sources. In this way, the dual representation of the noise spectral density in terms of impedance and admittance fields is recovered. A remarkable achievement is that from the knowledge of the bulk Langevin sources at a hydrodynamic level it is possible to calculate the noise spectra of non-homogeneous structures even for nanometric devices. The method is validated by comparing the results of the present scheme with those obtained from self-consistent Monte Carlo approaches for different structures of interest.