Photocurrent-voltage relation of resonant tunneling diode photodetectors

We have investigated photodetectors based on an AlGaAs/GaAs double barrier structure with a nearby lattice-matched GaInNAs absorption layer. Photons with the telecommunication wavelength $λ=1.3$ μm lead to hole accumulation close to the double barrier inducing a voltage shift $ΔV(V)$ of the current-voltage curve, which depends strongly on the bias voltage $V$⁠. A model is proposed describing $ΔV(V)$ and the photocurrent response in excellent agreement with the experimental observations. According to the model, an interplay of the resonant tunneling diode (RTD) quantum efficiency $η(V)$⁠, the lifetime of photogenerated and accumulated charge carriers $τ(V)$⁠, and the RTD current-voltage relation in the dark determines best working parameters of RTD photodetectors. Limitations and voltage dependencies of the photoresponse are discussed.