Quantum-dot infrared photodetector with lateral carrier transport

In this letter, we present a normal-incident quantum-dot infrared photodetector. The detection principle is based on intersubband transition between the p states and the wetting-layer subband in the conduction band of self-assembled In(Ga)As/GaAs quantum dots. Carrier transport takes place in a channel next to the quantum-dot layers. The photoresponse is peaked at λ=6.65 μm (186 meV) and reaches a maximum value of over 11 A/W at T=30 K with a wavelength resolution of 12%. Detector response time τ is determined to be about 0.8 ms. Temperature and frequency dependence of the detector structure are discussed.