Title:  Carbon Nanotube Based Thin Film Transistors for Gas Sensing and Electronic Applications

Committee: 

Dr. Kumar, Advisor

Dr. Chatterjee, Co-Advisor    

Dr. Mukhopadhyay, Chair

Dr. Hesketh

Abstract:

The objective of the proposed research is to fabricate and analyze carbon nanotube (CNT) network thin film transistors (TFTs) and small circuits units by photolithography and printing techniques, to perform systematic studies of the performance variability of fabricated CNT-TFTs, and to apply them as sensors for gas identification. CNT-TFTs are promising candidates for future electronic devices because they cannot only meet the requirements of aggressive scaling of physical dimensions, but also have enormous potential for future flexible microelectronics. Device-to-device performance variability can pose challenging problems for its use in different applications. To address this, a variability study has been performed through a combination of experimental and theoretical analysis, which deciphers the effects from different sources of variation including % of metallic CNTs, threshold voltage, CNT mean length, and CNT network density. CNT-TFT based gas sensors exhibit significant advantages in pollution monitoring because of their fast response, high sensitivity and stability. The sensor response has been examined when exposed to NH3 and NO2 with different concentrations. A convolution based model has been developed to investigate sensor response and utilized for gas identification, which remedies the lack of selectivity of the CNT based sensors. Printed CNT-TFTs have been fabricated using aerosol jet printer which possesses tremendous advantage in design versatility, operational flexibility, and promising for cost-effective and scalable production of future flexible/wearable devices. Some circuit units using CNT-TFTs will be fabricated and its functionality will be analyzed.