Most thermoluminescent materials are created using crystal growth techniques; however, it would be of great utility to identify those few thermoluminescent materials that can be deposited using simpler methods, for example to be compatible with the early portions of a silicon integrated circuit or microelectromechanical fabrication process. In this work, thin films of yttrium oxide with a terbium impurity (Y2O3:Tb) were deposited on silicon wafers by electron beam evaporation. The source for the Y2O3:Tb was made by combining Y2O3 and Tb4O7 powders. The approximate thicknesses of the deposited films were 350 nm. After deposition, the films were annealed at 1100 C for 30 s to improve crystallinity. There is a strong correlation between the x-ray diffraction (XRD) peak intensity and the thermoluminescent glow curve intensity. The glow curve displays at least two peaks at 140 C and 230 C. The emission spectra was measured using successive runs with a monochromator set to a different wavelength for each run. There are two main emission peaks at 490 nm and 540 nm. The terbium impurity concentration of approximately 1 mol% was measured using Rutherford backscattering spectrometry (RBS). The Y 2O3:Tb is sensitive to UV, x-ray, and gamma radiation. The luminescent intensity per unit mass of UV irradiated Y2O 3:Tb was about 2 times that of x-ray irradiated TLD-100.
Bibliographical noteFunding Information:
We would like to acknowledge financial support from the Defense Threat Reduction Agency ( HDTRA1-10-1–0007 ) our collaborator Dr. Eduardo G. Yukihara from Oklahoma State University for sharing data on rare earth doped dielectrics and Greg Haugstad from the Characterization Facility of the University of Minnesota for doing the RBS measurement. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from NSF through the MRSEC program. All thin film processing was done in the Minnesota Nano Center of the University of Minnesota.
- Rare earth
- Thin film