We present optical nanoantennas designed for applications that require processing temperatures larger than 800 degrees C. The antennas consist of arrays of Re/Pt bilayer strips fabricated with a lift-off-free technique on top of etched trenches. Reflectance measurements show a clear plasmonic resonance at approximately 670 nm for light polarized orthogonal to the strip axis. The functionality of the antennas is demonstrated by growing single-walled carbon nanotubes (CNTs) on top of the antenna arrays and measuring the corresponding Raman signal enhancement of selected CNTs. The results of the measurements are quantitatively discussed in light of numerical simulations which highlight the impact of the substrate.