CVD DIAMOND SENSING DEVICES (INVITED)

摘要

The use of diamond in sensors, MEMS microstructures, and electrochemistry has become an interesting research topic because CVD diamond has numerous material advantages for sensing applications. This paper reports on the use of CVD diamond for chemical sensing in air and liquid environments. For gas sensing, the approach integrates gas-sensitive electrodes with diamond layers as deposited on supporting substrates to fabricate gas sensitive diodes. Gas detection for H_2, O_2, CO, and hydrocarbon gases has shown high sensitivity and fast response time over a very wide temperature range ( > 600℃). Detection mechanisms of these microsensors have also been studied. For chemical sensing in liquid, high quality and conductive diamond films have been found to exhibit active voltammetric response without the need for surface pretreatment. The limits of detection and sensitivity for diamond have been further improved by shrinking the electrode geometry with microfabrication techniques. Various geometric structures of diamond microelectrode arrays such as microtips, microdiscs, and microbands have been designed and fabricated. Diamond microelectrode arrays for electrochemical sensing in liquid' media have been achieved and exhibited higher sensitivity than conventional planar diamond film and other microprobes. Diamond microstructures have broad practical applications for chemical sensing and demonstrate operation at temperature, dynamic range, sensitivity, and radiation with far better performance than those based on silicon and other materials.