Normal-incidence intersubband (In, Ga)As/GaAs quantum dot infrared photodetectors

Abstract

We report the device performance of normal-incidence (In, Ga)As/GaAs quantum dot intersubband infrared photodetectors. A primary intersubband transition peak is observed at the wavelength of 13 μm (E0→E1) and a secondary peak at 11 μm (E0→E2). The measured energy spacing in the conduction band of the quantum dots is in good agreement with low temperature photoluminescence measurement and calculations. A peak detectivity of 1×1010 cm Hz1/2/W at 13 μm was achieved at 40 K for these devices.