| AVS 58th Annual International Symposium and Exhibition | |
| Electronic Materials and Processing Division | Wednesday Sessions |
| Session EM-WeA |
| Session: | Defects in Electronic Materials |
| Presenter: | Richard Rosenberg, Argonne National Laboratory |
| Authors: | R.A. Rosenberg, Argonne National Laboratory Y. Choi, Argonne National Laboratory V. Kalyanaraman, Argonne National Laboratory M. Kareev, University of Arkansas at Fayetteville J. Tchakhalian, University of Arkansas at Fayetteville S. Balaz, Ohio State University L.J. Brillson, Ohio State University |
| Correspondent: | Click to Email |
SrTiO3 and related perovskite materials are increasingly being utilized in a wide range of electrical applications. Furthermore, SrTiO3 is often used as a substrate for growth of thin film structures. Thus, knowledge of its defect structure and, in particular, their depth dependence is crucial for understanding their impact on conductivity and optical phenomena. In the present work we utilize the limited penetration depth of x-rays to study the near-surface properties of SrTiO3 substrates and epilayers and compare the results to analogous measurements using electrons. For an incidence angle of 10 degrees, the x-ray penetration depth varies between 22 and 207 nm as the energy changes from 600 to 1500 eV. For electrons the mean penetration depth varies from 3 to 90 nm as the energy changes from 0.5 to 5 keV. Thus, by obtaining x-ray excited optical luminescence (XEOL) and cathodoluminescence (CL) spectra as a function of x-ray or electron energy, it is possible to probe the near-surface region with nm-scale resolution. We will present energy-dependent XEOL and CL data from several SrTiO3 samples. The luminescence spectra show features that can be assigned to Ti3+ (~1.6 eV) and oxygen-related (1.9-2.9 eV) defects, but the relative intensities differ between XEOL and CL. We will discuss the results in terms of the respective mechanisms, previous CL studies [1,2] and theoretical models.
This work was performed at the Advanced Photon Source and was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-06CH11357. We gratefully acknowledge
Ohio State University support from Army Research Office Grant
W911NF-10-1-0220
1. J. Zhang, et al, J. Vac. Sci. Technol. B 26, 1456 (2008).
2. J. Zhang, et al, Appl. Phys. Lett. 94, 092904 (2009).