Investigation on visible light photoresponse of cuprous oxide and zinc oxide heterojunctions on carbon nanotube

• Main Author: Chay, Junwei
• Other Authors: Du Hejun
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/60993
• Institution: Nanyang Technological University

Zinc oxide (ZnO) is one of the prominent semiconductors with band gap of 3.37eV. Due to its wide band gap, ZnO is only able to response to ultraviolet light under room temperature. To maximise the functionality of ZnO, many efforts have been made to investigate ZnO-based p-n heterojunction. Cuprous oxide (Cu2O) is one of the first known p-type semiconductor available. It is non-toxic and has high excitonic properties and large exciton binding energy. Since ZnO exists mainly as n-type semiconductor, the combination with Cu2O form a p-n junction which further promotes the flow of electrical current thus implying the increase in electrical conductivity. In this report, in order to investigate the photoresponse of ZnO and Cu2O under the visible light region, both semiconductors were coated onto carbon nanotubes (CNTs) using sputtering. The coated CNTs samples were subjected to white light emitting diode (LED) light of different intensities and also LEDs of different wavelength. A series of tests and analyses were also carried out to further understand both the physical and chemical properties of CNTs, ZnO and Cu2O and their interactions. The results in this reports show that the coating of ZnO and Cu2O did improve the performance of the CNTs samples and all samples are able to response to the visible light.