Noise in short n+-n--n+GaAs diodes

Noise measurements in a short, near-ballistic, n
⁺
-n
^-
-n
⁺
GaAs diode are reported. The device had a linear characteristic below 100 mA. It showed
1/f
noise at low frequencies and a white noise close to the thermal noise of the device conductance
g
at high frequencies. The
1/f
noise is most likely mobility fluctuation noise; we evaluated Hooge's parameter α and found a value of 1.95 × 10
^-6
at room temperature and 0.959 × 10
^-6
at liquid nitrogen temperature. We also observed a
1/f
noise spectrum turning over into
1/f
^0.5
spectrum at 77 K.