A novel and promising method for the detection of chemical molecules in a liquid was realized using a con tact of p-CuO and n-type ZnO semiconducting ceram ics (p-n contact). When this device is soaked in an alco hol, a characteristic current-voltage (I-V) relation is observed. It is possible to discriminate the chemical species and to estimate the alcohol concentration in al cohol-water solutions. Since the characteristic I-V re lation occurs from chemical interaction between alco hol

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... and semiconductor surfaces at the con tact interface, the p-n contact is expected to be applica ble for the detection of other chemical molecules in a liquid-or gas-state.