I–V and Differential Conduction Characteristics
of an AlGaAs/GaAs Lateral Quantum Dot Infrared Photodetector
A new infrared detector design, henceforth referred to as a lateral quantum dot infrared photodetector (LQDIP), with the potential for a tunable internal spectral response was investigated. In this design, InAs quantum dots are buried in a GaAs quantum well, which is in turn tunnel-coupled to a second GaAs quantum well. Photoexcited electrons from the quantum dots are expected to tunnel over to the second well, where they are then swept out via a lateral (perpendicular to the growth direction) bias voltage. The lateral photocurrent is in part directed to tunnel into the second quantum well by the depletion field of a narrow pinch-off gate, applied vertically (parallel to the growth direction). Under a proper biasing arrangement, this detector architecture is expected to exhibit the ability to tune to select infrared frequencies as well as operate with reduced dark currents and unity gain in the second well. The LQDIP detector architecture, operating principles and conditions, and preliminary results of I–V, photocurrent, and differential conductance measurements are all discussed.