STM/STS study of superconducting diamond

We present a scanning tunneling microscopy/spectroscopy (STM/STS) study of synthetic polycrystalline boron–doped diamond in the temperature range 0.5–4.3 K. At 4.3 K the sample–surface was very non–uniform and tunneling I(V) spectra were typical for p–type semiconductors. After cooling below the superconducting transition temperature, we detected and measured the superconducting gap of diamonds. At temperatures around 0.5 K the energy gap was around 0.8 and 1 mV (for two differentsamples).