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Study of Impact Excitation Processes in Boron Nitride for Deep Ultra-Violet Electroluminescence Photonic Devices

Wickramasinghe, Thushan E.
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1565311409028495

Abstract Details

2019, Master of Science (MS), Ohio University, Electrical Engineering & Computer Science (Engineering and Technology).
Studies and contemporary technology have shown the feasibility of developing direct current (dc) driven III-nitride deep ultra-violet (UV) photonic devices through band gap engineering of epitaxially grown hetero-structures. Alternatively, one can consider developing deep ultraviolet (UV-C) light sources operating on the principles of hot electrons impact excitation processes in a boron nitride (BN) phosphor. It was shown that high quality BN nanosheets (BNNSs) can generate excitonic emission at 225 nm under electron excitation of 6 kV and thus can be considered as a potential material for developing alternating current (ac) driven thin electroluminescence (ACTEL) devices. In this work we consider a theoretical approach based on the Bringuier model [J. Appl. Phys. 70, 8 (1991), pp. 4505-4512.] for generating luminescence in the UV-C region from hexagonal BN (h-BN) through impact excitation under a high electric field. Applying the Lucky Drift Model and Born approximation to high field electronic transport in h-BN we took into account ballistic and drift mode models to optimize a prospective device performance. The original model concerning Mn luminescent centers embedded in a ZnS host was adopted for an un-doped h-BN host. We used the lucky drift approach to study the probability of primary electrons encountering a collision within the lattice and thereby arrive at an efficiency of secondary electrons being excited to generate the desired near band edge (NBE) transmissions. It was found that in ACTEL device biased at 8.5 × 105 𝑉𝑐𝑚−1 a primary electron encountering an impact excitation would travel ~20 μm in a single h-BN layer before gaining sufficient kinetic energy to undergo a second collision which significantly reduces the device efficiency. Furthermore, we have also considered the efficiency of electroluminescence (EL) in h-BN by using the impact excitation rate theory developed by Neumark [Phys. Rev. 116, 6, (1959), pp. 1425-1432.] for a ZnS lattice. While our model has good agreement with the literature on ZnS based ACTEL devices (i.e. 17(𝑉𝑏⁄𝑉0)% where Vb is the barrier voltage of the of the device and V0 is the voltage drop the electrons pass through as defined by Neumark), we found that the EL efficiency for h-BN is much lower 0.3(𝑉𝑏⁄𝑉0)%. Using an estimate for 𝑉𝑏⁄𝑉0 at a 110 V applied voltage we found the external efficiency of the h-BN to be 0.04%. Finally, we have simulated the ACTEL device’s efficiency by considering different h-BN layer thickness and the applied field in order to optimize the device.
Wojciech Jadwisienczak (Advisor)
Savas Kaya (Committee Member)
Jeffrey Dill (Committee Member)
Justin Frantz (Committee Member)
97 p.
Engineering
Deep ultra-violet light; electroluminescence; impact excitation; hexagonal boron nitride

Recommended Citations

Citations

  • Wickramasinghe, T. E. (2019). Study of Impact Excitation Processes in Boron Nitride for Deep Ultra-Violet Electroluminescence Photonic Devices [Master's thesis, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1565311409028495

    APA Style (7th edition)

  • Wickramasinghe, Thushan. Study of Impact Excitation Processes in Boron Nitride for Deep Ultra-Violet Electroluminescence Photonic Devices. 2019. Ohio University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1565311409028495.

    MLA Style (8th edition)

  • Wickramasinghe, Thushan. "Study of Impact Excitation Processes in Boron Nitride for Deep Ultra-Violet Electroluminescence Photonic Devices." Master's thesis, Ohio University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1565311409028495

    Chicago Manual of Style (17th edition)

ohiou1565311409028495
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© 2019, all rights reserved.
This open access ETD is published by Ohio University and OhioLINK.