Full text
| |
| Author(s): |
Tiago Carneiro Gomes
Total Authors: 1
|
| Document type: | Doctoral Thesis |
| Press: | Bauru. 2018-07-02. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Ciências. Bauru |
| Defense date: | 2018-03-27 |
| Advisor: | Neri Alves |
| Abstract | |
ZnO thin film transistors have been applied as ultraviolet (UV) radiation sensors in order to prevent damage to skin's health. However, the performance of ZnO transistor depends on the preparation conditions of both ZnO layer and gate dielectric. This work aims to produce and evaluate ZnO/Al2O3 transistors by studying simultaneously the parameters regarding the preparation of ZnO and Al2O3 layers, as well as the fabrication of ZnO transistors with a standard dielectric (ZnO/SiO2), under different conditions of working. It is intended to investigate the conditions to apply ZnO transistors as UV sensor. The experiments involve the deposition of ZnO films by sputter coating and spray pyrolysis of a solution of zinc acetate. SiO2 dielectric was commercially purchased, while Al2O3 was grown by anodization. The transistors were fabricated under different conditions, which were established by both experimental design Taguchi and Plackett-Burman methods. The responses from the characterization were interpreted by statistical techniques (ANOVA). The results showed that optimized Al2O3 films exhibit leakage current until 10E-10 A and dielectric constant of ~13. It was essential to identify the most important parameters regarding to preparation of ZnO films by pyrolysis spray in order to fabricate ZnO/Al2O3 transistors with mobilities of ~4,5 cm2/Vs. UV sensors based on ZnO/SiO2 transistors showed mobilities from 0,1 to 12 cm2/Vs and demonstrated that the sensitivity of the UV sensor depends on parameters related to working conditions. Therefore, it is of great importance the understanding of the parameters involved in the production of the devices, as it allows to refine the process in the search for the high performance of low cost materials as well as optimize the device for application as UV sensor. (AU) | |
| FAPESP's process: | 14/13904-8 - Investigations on ZnO and TIPs-Pentacene based transistors for printed hybrid inverter circuit |
| Grantee: | Tiago Carneiro Gomes |
| Support Opportunities: | Scholarships in Brazil - Doctorate |