A five-period normal-incidence (In, Ga)As/GaAs quantum-dot infrared photodetector

Abstract

We have measured the optical and electrical properties of a five-period normal-incidence (In, Ga)As/GaAs quantum-dot infrared photodetector. A primary intersubband transition peak is observed at the wavelength of 10.2 μm and a secondary one at 9.4 μm. Excellent electron transport and peak detectivity of 7×109 cm Hz1/2/W are achieved at 30 K, with a low bias responsivity of up to 70 mA/W at 0.6 V. We believe that an observed avalanche gain process is initiated by intersubband absorption in the quantum dots. The maximum responsivity due to this avalanche multiplication process is about 4 A/W at a bias of 1.0 V.