Nanostructure development in photodeposited, titania-based thin films
- PDF / 1,470,678 Bytes
- 8 Pages / 584.957 x 782.986 pts Page_size
- 49 Downloads / 214 Views
Timothy J. Boyle Sandia National Laboratories, Advanced Materials Laboratory, Albuquerque, New Mexico 87105 (Received 23 June 2009; accepted 31 August 2009)
Ultraviolet irradiation (l = 248 nm) was used to photocatalyze a solution of the heteroleptic titanium alkoxide (OPy)2Ti(TAP)2 [where OPy = pyridine carbinoxide and TAP = 2,4,6 tris(dimethylamino)phenoxide], leading to the deposition of a titania-based thin film only in the exposed region. The effect of water addition to the (OPy)2Ti(TAP)2 pyridine solution on the properties of the final photodeposited film structure was examined by using vibrational spectroscopy and electron microscopy. Under consistent optical exposure conditions, the amount of water added altered the nanoscale porosity of the final material produced. Films deposited from a solution with a 1:1 H2O/Ti content exhibited surface pores 100 nm in diameter, whereas a 4:1 ratio yielded 10-nm pores, and material produced from a 8:1 solution appeared fully condensed. In addition, the effect of postdeposition thermal treatments on the nanostructure and chemistry of the photodeposited films was examined. I. INTRODUCTION
Micro- and nanostructured metal oxide and hybrid thin films are of great interest for a wide range of applications that rely on the electronic, optical, chemical, and/or biological functionality associated with the effective control of multilength scale structure.1–4 Patterning of such films has been pursued by using a variety of strategies, including multistep, photolithographic processing, and material growth templating techniques.5,6 These strategies produce the desired structures via patterned removal of material or by influencing the spatial development of the film during deposition through controlled surface chemistry. In a related approach, solution-phase syntheses involving metal alkoxide precursors derivatized with an optically active chelating ligand have been used to produce thin films via standard sol-gel processing techniques. This process is often followed by patterned optical exposure to complete the formation of the final oxide network. Subsequent “developing” steps using solvents that dissolve the un-irradiated, incompletely condensed material reveal the optically patterned structure.7–9 An alternative to this postdeposition photoprocessing of homogeneous thin film materials is the optical initiation and control of the molecular assembly process at the onset of material formation. Thus, photopatterning of the solution itself can yield control over nano- and microscale structural development. In the context of the present work, a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2009.0411
3372
http://journals.cambridge.org
J. Mater. Res., Vol. 24, No. 11, Nov 2009 Downloaded: 13 Mar 2015
this approach has been used to demonstrate the directwrite deposition of titanium-oxide-based films from a specially designed alkoxide precursor [(OPy)2Ti(TAP)2, where OPy = pyridine carbinoxide and TAP = 2,4,6 tris (dimethylamino)phenox
Data Loading...
