| AVS 55th International Symposium & Exhibition | |
| Thin Film | Tuesday Sessions |
| Session TF-TuM |
| Session: | Applications of Atomic Layer Deposition |
| Presenter: | J.P. Chang, University of California, Los Angeles |
| Authors: | J. Hoang, University of California, Los Angeles J.P. Chang, University of California, Los Angeles |
| Correspondent: | Click to Email |
Radical enhanced atomic layer deposition (ALD) has been previously shown to enable the control of the Er3+ spatial distribution in Y2O3 thin films, thereby achieving an enhanced direct absorption cross section at 1540 nm and much improved photoluminescence with well-resolved Stark features.1 Given the larger index of refraction of Y2O3 compared to that of SiO2, this suggests that Er:Y2O3 thin films has the potential to achieve compact optical amplification. In this work, we report the utilization of radical enhanced atomic layer deposition to synthesize controlled concentrations and spatial distances of Yb and Er in Yb3+ co-doped Er:Y2O3 thin films and the corresponding improvement in their optical characteristics. The electronic energy level and a large absorption cross section of Yb3+ make it an effective sensitizer for Er3+. Thin films of approximately 10 nm are synthesized by sequential radical-enhanced ALD of Y2O3, Er2O3, and Yb2O3 at 350°C. The composition, microstructure, cation distribution, local chemical bonding and optical properties of the as-synthesized thin films were determined by x-ray spectroscopy, electron microscopy and photoluminescent measurements. To optimize the effect of the sensitizer and minimize the concentration quenching, the concentration of Yb3+ and Er3+ were controlled by changing the global deposition cycle sequence. Extended x-ray absorption fine structure analysis verified spatial control of Yb3+ and Er3+ in the Y2O3 host. Much improved effective absorption cross sections were estimated using the photoluminescence yield as a function of the pump power, as compared with measurements from thin films without Yb3+ sensitizers. From these measurements, an optimum concentration and spatial arrangement is chosen for the design of spiral ridge waveguide devices. These waveguides can achieve potential gains of two orders of magnitude over Er:SiO2 and an order of magnitude over ion implanted Al2O3.
1 Hoang, J., T. T. Van, et al. Journal of Applied Physics. 101(12).