Ms. Eryal Rhinehart · Optical Science and Engineering

About the Student

Eryal Nicole Rhinehart is a Master of Science student in Optical Science and Engineering at the University of New Mexico, with a concentration in photonics. She earned her Bachelor of Science in Mechanical Engineering with an aerospace concentration from North Carolina A&T State University. Her thesis research investigates how growth chemistry and annealing influence the structural and photoluminescent properties of ALD-grown ZnO thin films for optical thermometry. She has also gained research and engineering experience through internships at Sandia National Laboratories, Boeing, and Northrop Grumman.

Abstract

This thesis examines how atomic layer deposition (ALD) growth chemistry and annealing affect ZnO films for optical thermometry. As deposited ZnO/Al₂O₃/Cr-Au-Cr/Si stacks grown with H₂O or an O₃/H₂O sequence were compared to samples annealed at 700-1000 °C and characterized by scanning electron microscopy, X-ray diffraction (XRD), and continuous-wave (CW) and pulsed photoluminescence (PL). The O₃-assisted film rapidly annealed at 800 °C in argon produced the narrowest fitted ZnO (002) reflection and strongest recorded near-ultraviolet response. This near-ultraviolet emission, observed near 390 nm, is associated with near-band-edge recombination in ZnO. Comparatively, H₂O-grown films annealed at 700 °C in argon produced their strongest band edge recombination. At 900-1000 °C, neither tracked ZnO reflection remained detectable in the O₃-assisted films, whereas H₂O-grown films retained (200) after losing (002). CW-PL showed different atmosphere-dependent visible-emission trends for the two chemistries. These results demonstrate that annealing temperature alone does not determine ZnO performance. Growth chemistry, atmosphere, and thermal history jointly control the crystalline and electronic states that govern emission. The combined XRD, CW-PL, and pulsed-PL framework therefore provides a more defensible basis for selecting ZnO processing conditions for future nanosecond optical-thermometry measurements than any single characterization method.

Committee Members