Journal
APPLIED SURFACE SCIENCE
Volume 537, Issue -, Pages -Publisher
ELSEVIER
DOI: 10.1016/j.apsusc.2020.147895
Keywords
ZnO; Thin film; FET; Biosensor; Defects; Roughness
Categories
Funding
- Visvesvaraya Ph.D. Scheme - Ministry of Electronics & Information Technology, Government of India
- Visvesvaraya Young Faculty Research Award - Ministry of Electronics & Information Technology, Government of India
Ask authors/readers for more resources
The impact of surface defects in zinc oxide thin films on the performance of field effect transistor biosensors was studied, revealing a monotonic decrease in transconductance with increasing defect density but a non-monotonic behavior in antibody binding density. Optimization led to lower detection limits and higher sensitivity for the sensors, with the best performing sensor maintaining stability for 2 months.
In this work, the impact of surface defects in zinc oxide (ZnO) thin films on the performance of field effect transistor (FET) biosensors has been explored. Here, ZnO thin films have been fabricated using electron beam evaporation with various deposition parameters to tune the surface roughness and defect state density. The films have been deployed for sensing prostate specific antigen (PSA) after anti-PSA antibody immobilization. Interestingly, it has been observed that though the transconductance of the sensors degrade monotonically with increasing defect density, the antibody binding density has a non-monotonic behaviour due to enhanced steric hindrance effect beyond a certain limit of surface roughness. There is a variation of sensitivity by 15 times with different physical properties of ZnO and the optimized sensor has a PSA detection limit of 0.06 fM. Further, the sensor with the best sensitivity retains its performance upto 2 months while a non-optimized sensor with initial PSA detection limit of 0.1 fM has longevity of 4 months. Thus, it can be envisaged that tuning the surface defect state in ZnO FET biosensor is an essential requirement not only to ensure a low detection limit and high sensitivity but also to assure a reliable long term performance.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available