Low frequency noise and electrical characteristics of p-InAsSbP/n-InAs single heterostructures grown onto n+-InAs substrates have been measured in the presence of atmosphere containing ethanol vapor. Correlation between ethanol vapor density and electrical spectral noise density as well as the heterostructure resistance has been estimated, and possible reasons for such correlation have been discussed.

The frequency and current dependences of the optical output spectral noise density, Slph, in p-InAsSbP/n-InAs infrared light emitting diodes (LEDs) has been measured for the first time. LEDs with emission centered at wavelengths lambda = 2.8 and 3.5 mu m have been studied. In both cases, in the frequency range 2 <= f <= 100 Hz the noise spectrum is 1/f like. At constant LED pumping current, Slph is proportional to the photocurrent squared (-Iph2). The 1/f noise intensity Slph for the LED with emission centered at lambda = 2.8 mu m is -2 times higher. In the LED pumping current range 0.02 <= ILED <= 0.1 A (60 <= jLED <= 300 A/cm2) the optical output 1/f noise is practically independent of ILED.The intensity of the LEDs' optical output 1/f noise is less than the intensity of the photodiode reverse bias current noise by -4 orders of magnitude.

Low frequency noise in P-InAsSbP/n-InAs infrared light emitting diode- photodiode pairs is investigated for the first time at 300 K. It is shown that photocurrent fluctuations under LED illumination are smaller than photocurrent fluctuations under a black body illumination. When the photodiode is illuminated by LED, the spectral noise density follows the 1/f dependence. In the case of a black body illumination we observe a significant contribution of generation-recombination noise.

Low frequency photocurrent noise, as well as the forward current noise are studied for the first time in mid infrared InAsSbP/InAs double heterostructure photodiodes at 100 K. Two types of photodiodes are identified. For the first type, the spectral noise density, SI, depends on frequency as 1/f(gamma). For the second type, generation recombination (GR) noise component dominates. Our results show that in those samples, it is one and the same local center that is responsible for the noise over the entire photocurrent range. The forward current noise in all samples is lower than that previously observed in InAsSbP/InAs single heterostructure photodiodes at 77 K. In samples demonstrating 1/f gamma noise, the spectral noise density, S-I, is proportional to the square of the current. In samples with GR noise, we also observe S-I similar to I-2 dependences in a certain current range. At higher currents, the noise decreases or tends to saturate. We show that at 100 K, the Nyquist noise is dominant and can be used for estimating the specific detectivity at photocurrents Iph < 5.10(-9) A for samples showing 1/f(gamma). noise, and at Iph < 2.10(-9) A for samples presenting GR noise component. At higher Iph the photocurrent noise should be also taken into account.

Low frequency reverse current noise is studied for the first time in InAsSbP/InAs double heterostructure (DH) photodiodes in the frequency range 1 Hz-10(4) Hz at 300 K and 100 K. At room temperature, the noise in the DH photodiodes is 1/f and might be significantly lower (by similar to 17 dB) than in single heterostructure InAsSbP/InAs photodiodes. In the practically most important regime of low reverse currents, I-rb, the current dependence of spectral noise density is proportional to I-rb(2), both at 300 K and 100 K. The reverse current noise might provide the limit for the detectivity of DH photodiodes at I-rb > 3 x 10(-6) A at 300 K and I-rb > 8 x 10(-9) A at 100 K.