Comparison of the electrical behavior of Schottky diodes built on the nucleation and growth surfaces of polycrystalline diamond

In this work free-standing polycrystalline diamond was used to build Schottky diodes both on nucleation and growth surface of different films, in surface contact geometry, using gold and aluminum electrodes. The surface films were characterized by micro-Raman spectroscopy and Atomic Force Microscopy. The current–voltage characteristics of the devices were measured in a temperature range from 50 K to room temperature. The diodes showed a barrier height, attributed to the interface grain–metal, ranging from 1.26 to 1.74 V and an ideality factor from 1.4 to 1.8. All the diodes revealed the presence of deep states of energy, and its density close to the Fermi level ranges from 2 × 1012 to 8 × 1016 eV− 1 cm− 3. These different characteristics were then related with both the films quality and the surface. The hypothesis of using the nucleation surface for building electronic devices is discussed.