Gas sensors based on 2,9,16,23-tetra(2,6-dimethylphenoxy)metallophthalocyanine (TDMP- MPc ) films on interlocking silver electrodes were fabricated by solvent casting from chloroform solutions containing 2,9,16,23-tetra(2,6-dimethylphenoxy)copper, cobalt or nickel phthalocyanine ( TDMP - CuPc , TDMP - CoPc or TDMP - NiPc ). The sensitivity of the gas sensors to the presence of NO 2 and the depletion of O 2 was investigated. It was confirmed that the gas sensors based on TDMP - CuPc and TDMP - CoPc films could detect 1 ppm NO 2 at room temperature and that the current responses to the presence of NO 2 and the depletion of O 2 were considerably quick. These results indicate that adsorption and desorption of NO 2 and O 2 on the surfaces of TDMP - MPc films are easily achieved at room temperature.

We have evaluated the electrical degradation of the Zincoxide(ZnO) varistors added two kinds of additives by the V-I measurements and the improved ICTS method. Results of the V-I characteristics show that both the characteristics of varistors added Bi2O3 and CoO and those added Bi2O3 and MnO2 were recovered by thermal annealing. This indicates that the distribution of O2-ion changed by applying voltage was returned to the initial condition by thermal annealing. Results of the improved ICTS measurement show that the trap density for varistors added Bi2O3 and CoO decreased after degradation. Trap levels for varistors added Bi2O3 and MnO2 became shallower after degradation. The result of simulation shows that varistors with narrow distribution of trap levels, deep trap levels and the low donor density have excellent nonlinear characteristic.

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