Effect of Adhesive Layers on Photocurrent Enhancement in Near-Infrared Quantum-Dot Photodetectors Coupled with Metal-Nanodisk Arrays

Plasmon-enhanced planar Ge/Si photodetectors with Ge quantum dots on silicon-on-insulator substrates coupled with regular arrays of metal nanodisks on their surface are developed. It is found that the introduction of adhesive layers necessary for the formation of stable nanostructures from noble metals leads to the suppression of surface plasmon resonance. The selection of aluminum nanodiscs, which require no adhesive layers, increases the efficiency of photodetectors by 40 times at a wavelength of 1.2 μm and by 15 times at λ = 1.65 μm.