Noise characterization and device parameter extraction of a p-type strained layer quantum-well infrared photodetector

Dark current noise measurements between 101 and 105 Hz were carried out on a compressively strained p-type InGaAs/AlGaAs quantum-well infrared photodetector as a function of temperature and bias voltage. The measured noise can be attributed to number fluctuation noise associated with the generation and recombination of holes from and to the quantum-well bound states and the extended valence-band states. At low bias the number fluctuation noise translates into current fluctuation noise via hole diffusion, where as at higher-bias values the coupling is via the hole drift current component. Our measurements indicate that the field-induced barrier lowering and the Schottky image effect strongly influence the device characteristics. In addition we observe that the thermally generated heavy holes diffuse, at low fields, on the average to the nearest neighboring quantum well where they subsequently recombine. This recombination process is triggered by hole scattering with the acceptor centers.