The improvement of optical properties of tunnel coupled quantum wells of GaAs/AlGaAs by surface plasmonic effects

Metal-semiconductor hybrid structures have gained attention over the decades for enhancing semiconductor optical performances through the excellent absorption properties of plasmonic metals. In this study, we investigated plasmonic enhancement in GaAs/Al_0.36Ga_0.64As tunnel-coupled quantum wells with Au layers of two thicknesses and a titanium dioxide spacer layer. Our investigation was based on an analysis of temperature- and excitation-dependent photoluminescence (PL) intensity. A thicker Au layer was found to increase PL intensity. Electron temperature and scattering energy rate analyses explained this behavior as the result of plasmonic effects-driven amplified excitation power. Notably, this hybrid structure demonstrated high PL intensity even at low excitation densities. Therefore, this work advances the understanding of plasmonic effects in semiconductor structures and reveals a pathway to high PL intensity at low excitation densities for more efficient near-infrared optoelectronic devices.