A technique compatible to IC process has been presented to prepare gas sensing chips the lightly-doped region of nanoelectronic devices are grown with different sensing materials to form a gas sensor array. During gas sensing, individual nanodevice was Joule-heated, reducing power consumption to microWatts/device, solving the current high power consumption problem. With self-calibration of temperature, humidityinterfering gas, problems like cross-sensitivity, quantification, specificitysensitivity are solved. A demonstration of I+Nose with smart phone was presented for CO detection.