Lorentzian noise in the two-dimensional electron gas of AlxGa1-xAs/GaAs quantum wells

Current noise spectra S-I(omega) are reported on samples grown by the molec ular beam epitaxy technique, with current-carrying contacts, acting as sour ce and drain, and two probes extending into the two-dimensional electron ga s (2DEG) of the AlGaAs/GaAs quantum well, in the range 77-295 K for frequen cies of 10 Hz to 1 MHz. The time constants are almost independent of temper ature and the current dependence is close to linear. The noise is interpret ed as Lorentzian-modulated shot noise of the 2DEG current. (C) 1999 America n Institute of Physics. [S0021-8979(99)08323-1].