A study of the coupling efficiency versus grating periodicity in a normal incident GaAs/AlGaAs multiquantum well infrared detector

Abstract
A detailed study of the dependence of coupling quantum efficiency on the grating periodicity of planar metal grating coupled GaAs/AlGaAs quantum well infrared photodetectors has been made in this work. Five different detector samples with grating periodicities of Λ=1.1, 3.2, 5, 7, and 10 μm have been fabricated for the present study. The results showed that the device with a 5 μm grating periodicity gave the best front‐side coupling efficiency, which was in good agreement with our theoretical prediction. A single pass quantum efficiency (η) of 11% was achieved for the front‐side illumination at λp=9.8 μm and T=77 K.