Wavelength-Specific Ultraviolet Photodetectors Based on AlGaN Multiple Quantum Wells

The detection of a specific spectral line in ultraviolet in the presence of broadband ambient lighting is necessary for many applications. We report wavelength-selective photodetection using AlGaN multiple quantum wells grown by molecular beam epitaxy. A near-Gaussian photoresponse peak at 300 nm with a width of 17 nm was achieved in the lateral photocurrent, along with a much faster transient response compared with the devices based on bulk AlGaN. The wavelength selectivity, controlled by the formation and subsequent splitting of excitons, was achieved by the optimization of the alloy properties of the barrier layers, reducing the leakage of photogenerated carriers into the active region.