Low frequency noise in reverse biased P-InAsSbP/n-InAs infrared photodiodes

We report the first experimental study of low-frequency noise in reverse biased P-InAsSbP/n-InAs infrared photodiodes at 300 K and 77 K. At room temperature, the current noise spectral density, S-I, depends on frequency as 1/f over the entire current range and tends to the Nyquist noise when the frequency increases. At small reverse currents I-rb <= 3 x 10(-5) A, S-I is proportional to I-rb(2); at higher currents this dependence changes to S-I similar to I-rb(4). With temperature decrease down to 77 K, S-I becomes proportional to I-rb(0.5) , while the reverse current decreases and the differential resistance grows by 4 orders of magnitude. The noise was also studied in the photovoltaic mode at 100 K, where S-I is proportional to I-ph(2). We conclude that at 100 K, the Nyquist noise is dominant and can be used for estimations of the specific detectivity of P-InAsSbP/n-InAs diodes.