Ti-DLC薄膜压阻性能及载流子输运行为研究OA北大核心CSTPCD

Diamond like carbon(DLC)film was a promising candidate for microelectromechanical system(MEMS)piezoresistive sensors owing to its excellent mechanical properties and sensitivity.The effects of carrier transport behavior and the role of operating conditions(such as temperature,humidity,etc.)on piezoresistive performance of metal-doped DLC were still unclear.In this work,Ti doped diamond like carbon(Ti-DLC)films with Ti atom fraction ranging from 0.43%to 4.11%were prepared using high-power pulse magnetron sputtering,where the high-throughput conception was introduced for film deposition.Effects of the doped Ti content on microstructure,electrical behavior and piezoresistive properties of the films were studied under various humidity environments.The results indicated that the doped Ti atoms were uniformly dissolved in the diamond like carbon matrix,accompanying typical amorphous characteristics for the Ti-DLC films regardless of Ti atom fraction changing from 0.43%to 4.11%.Furthermore,all the Ti-DLC films demonstrated distinct semiconductor feature,where the electrical resistivity was reduced with the increase of temperature in the range of 200-350 K.Particularly,the carrier transport was dominated by Mott type conduction with three-dimensional range hopping conduction from 200 to 270 K,while the thermal activation transport served as the conductive mechanism in the temperature range of 270-350 K.For the Ti-DLC films,the highest gauge factor(GF)was 95.1,and GF value increased with increasing relative humidity from 20%to 80%.This can be explained from reduction of the average distance between conductive cluster by introducing Ti atoms and a change in electrical resistance caused by adsorption of water molecules.