Temperature dependence of plasmon-enhanced photocarrier generation and diffusion in single InGaAs/GaAs quantum well

The optical plasmonic properties of metal nanoparticles have been used for enhancing the rate of photoabsorption and photoemission by molecules and semiconductors. In this work, we exploit the plasmonic effects for understanding the dynamics of photocarriers using single InGaAs quantum well (SQW) confined in GaAs barrier by placing plasmonic colloidal gold nanorods (AuNRs) on the GaAs capping layer. This coupling geometry creates enhanced near-field that is tightly localized at the AuNR-GaAs interfaces. As a result, the exciton generation is enhanced at the interface by the local field, and the carrier diffusion and recombination dynamics as a function of temperature can be studied by measuring the photoluminescence (PL) of the InGaAs that is embedded inside the GaAs. We compare the PL of the SQW with and without the AuNRs from 10 K to room temperature and observe that the PL enhancement factor and spectral linewidth peak at certain temperatures depending on incident excitation intensity. We use this trend to study the temperature dependence of carrier diffusion as well as the competition between radiative and nonradiative recombination rates with increasing temperature.