CHARACTERIZATION OF CU-CUTCNQ-M DEVICES USING SCANNING ELECTRON-MICROSCOPY AND SCANNING TUNNELING MICROSCOPY

Scanning electron microscopy and scanning tunneling microscopy are used to determine the morphology of CuTCNQ films made using solution phase and vapor phase spontaneous formation methods. Values of film thickness range from 0.1-20 mum. All the films, irrespective of their method of preparation, display roughness on the order of their thickness. On the other hand, the morphology of these films varied significantly with preparation procedure. Resistance data from Cu-CuTCNQ-M devices (where M = Cu, Al, or Cr) are reported as a function of timed exposure of the freshly made devices to various gasses. Only devices having a thin Al top metal show significant resistance (> 100 OMEGA for a 1 mm2 junction), and then only after exposure to air. We suggest that the electrical switching phenomena often reported in Cu-CuTCNQ-Al structures cannot be understood without considering the interfacial interaction between the CUTCNQ film and the top metal.