Xy. Chen et al., 1 F NOISE IN DELTA-DOPED GAAS ANALYZED IN TERMS OF MOBILITY FLUCTUATIONS/, Physical review. B, Condensed matter, 55(8), 1997, pp. 5290-5296
This paper presents 1/f noise measurements on Si delta-doped GaAs stru
ctures. The samples are characterized by Hall, magnetoresistance, and
Schubnikov-de Haas measurements. The distribution of electrons over th
e two lowest subbands in these structures varies with temperature and
illumination, and so does the noise. The 1/f noise is characterized by
the usual parameter alpha. We show in detail how to interpret the 1/f
noise in the two-subbands system. We find that alpha increases by a f
actor of 30 upon population of a second subband either by illuminating
the sample or by raising the temperature to 100 K. This strong increa
se in the 1/f noise is successfully described by the mobility fluctuat
ion model, where only the lattice scattering contributes to the 1/f no
ise. The 1/f noise of the electrons in both subbands can be characteri
zed by the same value of alpha(L)=0.4, which is strong support for the
model.