Effects of temperature on the surface plasmon resonance at a metal–semiconductor interface

The effects due to elevated temperatures on the surface plasmon (SP) at a metal–semiconductor interface are studied both experimentally and theoretically. In particular, a junction made of silver and amorphous silicon is fabricated and the interfacial plasmon is excited optically via the Kretschmann geometry. Both the reflectance and phase monitoring of the response of the junction have been studied as a function of temperature from 300 K to 380 K. Theoretical simulations have been carried out to understand the observed data, using a previously established model for the temperature-dependent optical constants of the metal, together with empirically fitted data for those of the semiconductor. Reasonable qualitative comparison between experimental data and simulation is obtained. It is found that the strength of the SP at the junction will decrease as temperature increases, and the methodology of the present experiment may provide a way to quantify such a decrease in the operation efficiency of the junction. In addition, it is shown that, by monitoring the resonance angle, such a junction may act as a temperature sensor with sensitivity possibly higher than the previous ones which employed a bare metal film in the Kretschmann geometry.