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Optical and Electrical Study of the Rare Earth Doped III-nitride Semiconductor Materials

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2016, Doctor of Philosophy (PhD), Ohio University, Electrical Engineering & Computer Science (Engineering and Technology).
The technological advantages of III-nitride semiconductors (III-Ns) have been demonstrated among others in the area of light emitting applications. Due to fundamental reasons limiting growth of InGaN with high Indium content, rare earth (RE) doped III-Ns provide an alternative way to achieve monolithic red, green, blue (RGB) emitters on the same III-Ns host material. However, the excitation efficiency of RE3+ ions in III-Ns is still insufficient due to the complexity of energy transfer processes involved. In this work, we consider the current understanding of the excitation mechanisms of RE3+ ions doped III-Ns, specifically Yb3+ and Eu3+ ions, and theories toward the excitation mechanism involving RE induced defects. In particular, we demonstrate and emphasize that the RE induced structural isovalent (RESI) trap model can be applied to explain the excitation mechanism of III-Ns:RE3+. Specifically, we have investigated the Yb3+ ion doped into III-Ns hosts having different morphologies. The observed emission peaks of Yb3+ ion were analyzed and fitted with theoretical calculations. The study of Yb3+ ion doped InxGa1-xN nano-rod films with varied indium (In) concentration shown the improvement of luminescence quality from the nanorod due to the presence of Yb dopant. Then we report the optical spectroscopy and DLTS study toward an Eu and Si co-doped GaN and its control counterpart. The Laplace-DLTS and optical-DLTS system developed in this work improved spectrum resolution compared to the conventional DLTS. The high resolution L-DLTS revealed at least four closely spaced defect levels associated with the Trap B, identified with regular DLTS, with activation energy 0.259±0.032 eV (Trap B1), 0.253±0.020 eV (Trap B2), 0.257±0.017 eV (Trap B3), and 0.268±0.025 eV (Trap B4) below the conduction band edge, respectively. Most importantly, a shallow hole trap was observed at energy 30±20 meV above the valence band edge of the GaN:Si,Eu3+ which can be attributed to the RESI hole trap. Furthermore, a study on the Eu3+ ion implanted In0.06Ga0.94N/GaN superlattices (SLs) is reported to illustrate the plausible way of improving the excitation efficiency of Eu3+ ion via material engineering. It was concluded that the presence of Eu3+ ion in SLs induces an additional compressive stress component modifying the piezoelectric field in SLs active layer giving rise to an extra freedom in material engineering process for efficient energy transfer from the SLs to the Eu3+ ion.
Wojciech Jadwisienczak (Advisor)
Savas Kaya (Committee Member)
Martin Kordesch (Committee Member)
Eric Stinaff (Committee Member)
Kodi Avinash (Committee Member)
Harsha Chenji (Committee Member)
212 p.

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Citations

  • Wang, J. (2016). Optical and Electrical Study of the Rare Earth Doped III-nitride Semiconductor Materials [Doctoral dissertation, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1478177382556951

    APA Style (7th edition)

  • Wang, Jingzhou. Optical and Electrical Study of the Rare Earth Doped III-nitride Semiconductor Materials. 2016. Ohio University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1478177382556951.

    MLA Style (8th edition)

  • Wang, Jingzhou. "Optical and Electrical Study of the Rare Earth Doped III-nitride Semiconductor Materials." Doctoral dissertation, Ohio University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1478177382556951

    Chicago Manual of Style (17th edition)