Less than 10–13W weak light response for quantum dots photodetector at room temprature

In the paper, we report a high photoexcited carrier multiplication photodetector operating at room temperature. The photodetector has double AlAs barriers in which a layer of InAs self-assembled quantum dots and thin quantum well is embedded in the center of the GaAs quantum well. Unlike previous AlGaAs QD-RTD, its shows high sensitivity to the weak light irradiation at low bias voltage and the operating temperature 300 K. Its current responsivity can reach about 7 × 10¹¹ A/W when 0.01pw 633nm light power and -0.5V bias added. And its response voltage of the capacitance transresistance amplifiers (CTIA) readout circuit shows 7mV at 80μs integration time and 300K. The readout voltage responsivity has reached about 2.7×10⁹ V/W. This high multiplication factor is achieved by the quantum dot induced voltage in the QD layer. The high sensitivity features of the photodetector make a promising choice for medical diagnosis, biomolecular science and environmental protection biological samples.