The field of nanophotonics is based on the ability to confine light to sub-diffractional dimensions. Up until recently, research in this field has been primarily focused on the use of plasmonic metals. One highly promising alternative are the surface phonon polaritons that can be supported with low-losses within polar dielectric and semiconductor species. However, these modes can only be supported within a relatively narrow, material specific spectral region referred to as the Reststrahlen band. Here, methods for broadening and shifting these Reststrahlen bands will be discussed, as well as the potential for expanding it using carrier-phonon coupling.