Study of charge transport through zinc oxide nanowire networks for transparent electrodes
Abstract/Contents
- Abstract
- Indium Tin Oxide (ITO) is a transparent conductor widely used for fabricating transparent electrodes in solar cells, OLEDs, flat screen displays, touch screens and electro-chromic windows. In recent years the demand for these electronic devices has shown a double digit growth. Since Indium is a rare element, the rising demand for transparent electrodes will drive up the cost of ITO multi-fold. Thus it is the need of the time to find a suitable alternative low cost transparent conductor that can replace ITO in transparent conducting electrodes. ZnO is a wide band gap semiconducting oxide (Eg ~ 3.4eV) that has the potential to replace ITO as a cheap and flexible transparent electrode material. ZnO nanowires (NWs) can be easily synthesized and n-doped using a solution based synthesis process. The solution processed ZnO NW thin films however have a high sheet resistance (~1k[ohm]/[cube] post annealing) that needs to be reduced further. Hence charge transport in ZnO NW thin films has been studied using various experimental and simulation based techniques to reveal the factors causing high sheet resistance. The effect of ZnO NW orientation on thin film sheet resistance has been studied by aligning ZnO NWs in-plane on substrates. 2D NW network simulations coupled with aligned ZnO NW thin film electrical measurements have revealed that the NW-NW junction resistance is the dominating factor affecting charge transport. Electrochemical impedance spectroscopy (EIS) characterization has experimentally confirmed the presence of high NW junction resistance and revealed that annealing affects NW junctions. TEM characterization of in-situ annealed NW junction and micro-Raman spectroscopy of annealed ZnO NW mat film have uncovered a fascinating picture of the effect of annealing on ZnO NW junctions. Furthermore a versatile E2D methodology has been developed by combining the EIS measurement technique with 2D NW network simulations for extracting individual NW junction resistance i.e. extracting nano-scale electrical properties from macro-scale EIS measurements. NW junction resistance predicted by E2D has been verified by fabricating and measuring individual ZnO NW junction and single ZnO NW devices. The E2D methodology has been shown to be promising to study charge transport in other 1D nano-structured transparent conducting ensembles. Various applications of ZnO NW thin film electrodes have been discussed and research work on further reducing the ZnO NW thin film sheet resistance has been presented.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2012 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Phadke, Sujay Abhay |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering |
| Primary advisor | Prinz, F. B |
| Primary advisor | Salleo, Alberto |
| Thesis advisor | Prinz, F. B |
| Thesis advisor | Salleo, Alberto |
| Thesis advisor | McGehee, Michael |
| Advisor | McGehee, Michael |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Sujay Abhay Phadke. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2012. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by Sujay Abhay Phadke
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...