Low-frequency noise characteristics of extended wavelength InGaAs infrared detector

In order to investigate the low frequency noise characteristics of extended wavelength (1.0-2.4 μm) InGaAs infrared detector, we fabricated a number of In0.78Ga0.22As mesa photodiodes with various areas and tested the low frequency noise of these detectors. The results indicate that the noise spectra in low frequency region are proportional to f - γ where γ is around 0.9 for all of the diodes. The investigation on relationship between low frequency noise and bias voltage shows that the dependence of low frequency noise on reverse bias is based on the dependence of dark current. Then the dependence of low frequency noise on dark current in these reverse-biased diodes was examined, the noise and dark current of several diodes were measured at same voltage. The results of the noise power spectral density at f = 1 Hz indicate that noise varies proportionally with the dark current. The relationship between mesa geometry and noise magnitude was also investigated. Low frequency noise of diodes with different mesa areas was compared and the noise exhibits a linear dependence on the mesa areas.