1 F NOISE IN AN ALXGA1-XAS/GAAS HETEROSTRUCTURE BETWEEN 77-K AND 300-K/

Low-frequency (LF) noise was measured on an AlxGa1-xAs/GaAs heterostru cture in the temperature range from 77 to 300 K. Two types of excess n oise, 1/f and an extremely broadened (EB) Lorentzian noise, were obser ved. Like van Die et al., we attributed the observed EB Lorentzian noi se to the real-space transfer of the electrons from the two-dimensiona l electron gas (2DEG) to the n-AlxGa1-xAs layer and vice versa. A good agreement of alpha values of the 1/f noise at high temperatures and t heir temperature dependences in the heterostructures with those of bul k n-GaAs indicate that the 1/f noise in the heterostructures has the s ame origin as in bulk n-GaAs.