Giant Enhancement in UV Response of ZnO Nanobelts by Polymer Surface-Functionalization
Abstract
Zinc oxide (ZnO) is one of the most important nanomaterials for nano-optoelectronics, sensors, transistors, and nanopiezotronics. Because of the unique piezoelectric and semiconducting dual properties, ZnO nanowires (NWs) and nanobelts (NBs) are the fundamental material for nanogenerators, which convert mechanical energy into electricity. With a band gap of ~3.4 eV and an exciton binding energy of 60 meV, ZnO has huge promise for optical applications, such as UV detection. However, because of the presence of point defects and confined dimensionality, the UV sensitivity of ZnO NWs and NBs is limited. In this paper, we demonstrate that the UV response of a ZnO NB based sensor has been enhanced by close to 5 orders of magnitude after functionalizing its surface with a polymer that has a high UV absorption ability. This giant enhancement in photoconductance is attributed to the energy levels introduced by the polymer lying in the corresponding band gap and in the conduction band of ZnO, which served as a "hopping" state and increased the excitation probability of an electron to the conduction band. This exciting discovery will greatly impact the applications of ZnO NWs/NBs for UV detection.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2007
- Accession Number
- ADA474086
Entities
People
- Ashok K. Sood
- Chang Shi Lao
- Dennis L. Polla
- Myung-chul Park
- Qin Kuang
- Yulin Deng
- Zhong L. Wang
Organizations
- Georgia Tech