| The successful utilization of microelectronic-based gas sensors (MOS Capacitor, MOSFET, MS, and MIS diodes) in many practical applications such as automotive, aeronautical, commercial, and environmental has not been achieved due to the limited operating temperature range of Si and GaAs semiconductors (less than 200;We have developed a novel family of diamond-based chemical gas sensors for the detection of hydrogen, oxygen and carbon monoxide at a higher operating temperature range than currently possible with Si- and GaAs-based microelectronic gas sensors. The new devices were fabricated in the form of a Pd/i-diamond/p;Detection mechanisms of the sensors have been developed. The hydrogen detection mechanism of the diamond-based MIS device is due to hydrogen dipole formation at the Pd/i-diamond interface and a subsequent change in the voltage distribution across the junction. The oxygen and carbon monoxide sensitivity of the CAIS device is attributed to the modification of the oxygen vacancies in the SnO;The current transport mechanisms of the sensors have been studied and gas adsorption effects on sensor parameters have been modeled. The current conduction mechanism of the sensors is Space Charge Limited, distinctively different from Si- and GaAs-based diodes. While no significant change was observed on the ideality factor, a change in the barrier height and tunneling factor of the sensors was found upon gas adsorption.;The findings of this study form the basis for the utilization of microelectronic devices in wide range of gas sensor applications, requiring large sensitivity, fast, repeatable, and reproducible response, wider operating temperature range, and stability in harsh environments. Furthermore, this study contributes a fundamental knowledge in the operating principles and sensing mechanisms of the high temperature-tolerant microelectronic gas sensors. |
