A method for the controlled direct growth of highly crystalline ZnO nanorods on a paper substrate is described. Despite the complexity and surface roughness which paper naturally presents, adequate surface modification enhances ZnO nanorod alignment and uniformity in growth. Large scale synthesis is also demonstrated. Hybrid PN junction diodes, also on paper substrates, show application toward flexible electronics.
Afsal Manekkathodi, Ming-Yen Lu, Chun Wen Wang, and Lih-Juann Chen
Department of Materials Science and Engineering, National Tsing Hua University
Cut clean paper to the desired size.
A: (Surface Modification) Deposit Gold/Si using non ultra high vacuum e-beam deposition.
or B: (Seeding Layer) Spin coat a thin ZnO film 10-15 times using a 5-10mM solution of Zinc Acetate (~100nm layer of ZnO)
Dry the substrate at room temperature for 3 minutes.
Heat the substrate at 90C to remove excess moisture and other residuals.
Dry the substrates at room temperature.
The following steps are used to create hybrid PN junctions,using ZnO nanorods grown on a paper substrate with a 50nm Gold layer.
Spin a PMMA layer to fill in gaps between nanorods.
Perform O2 plasma etching using 20sccm Argon and 40sccm Oxygen at 180W RF power.
Spin coat a layer of PEDOT:PSS to a thickness 0.5-1um thick.
Paste a thin Silver film to form the top electrode.
Quality and geometric features can be modulated by varying growth temperature, precursor or seeding solution molarity.
- Paper(PAPERON Multipurpose Paper, Asia Pulp and Paper Co. Ltd)
- Zinc Acetate (98%, Aldrich)
- Hexamethylenetetramine (99%,Aldrich)
- Zinc Nitrate
- Poly(methyl methacrylate)(PMMA)
- Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate)) PEDOT:PSS
Room temperature, Heating up to 90oC
- Spin Coater,
- E-beam Evaporator
- RIE system