InGaAs Quantum Dot Dual-Band Photodetector of Bipolar Photocurrent

We report a dual-band photodetector grown by molecular beam epitaxy. The device epi-structure includes a GaAs PN- and an InGaAs quantum dot PIN-photodetector in a two-terminal, back-to-back configuration. At room temperature, the photocurrent-voltage characteristics show a serpentine curve. Under zero bias, a positive photocurrent is detected as the optical wavelength (λ)=530 nm of incident light, and a negative photocurrent for λ = 950 nm.