Abstract
Quantum well infrared photodetectors were fabricated using a chemical wet etching method, defined on a GaAs/AlGaAs heterostructure. These devices utilized grid nanostructures for effective light coupling through the diffraction effect. By reducing grid widths close to the depletion of the quantum well, we observed a systematic increase in the normalized responsivity of the photodetectors, as a possible signature of the quantum size effect, with blue shift. We also achieved precise control of grid widths through wet etching that does not require an expensive processing instrument.