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GaN-based Semiconductor Devices: Theoretical Study of the Electronic and Optoelectronic Characterization Authors: J. Stiens, S. Rabbaa and G. Shkerdin Publisher: Lambert Academic Publishing Publication Date: Dec. 2014 Number of Pages: 212 ISBN: 978-3-659-55781-1
Abstract: Nitride-based materials still offer opportunities for the development of new electronic and optoelectronic applications. From the seventies of the 20th century, the GaAs and GaAs/AlGaAs structures were considered as mature family materials for many electronic applications due to their lattice matching and high carrier mobility. In the beginning of the 21th century, these materials are step by step replaced by GaN and GaN/AlGaN structures in many applications due to their high polarization, chemical and physical stability, and wide bandgap.
In this work we study theoretically the electronic and optoelectronic properties of GaN and AlGaN/GaN structure, and we conceive their applications. We have tested the triangular quantum well model for the high electron mobility transistors (HEMTs). The two dimensional electron gas (2DEG) sheet density and the current-voltage (I-V) characteristics of the AlGaN/GaN HEMT are determined. We have discussed in detail the use of GaN-based HEMTs in fabricating chemical and biological sensors.
The plasmon frequencies of the 2DEG in the HEMT have been calculated. The sensitivity of the tunability of these frequencies is considerable, especially by using a variable applied gate voltage. The interaction between radiation and plasmons has many applications in terahertz (THz) spectrum. Optoelectronic characterizations of AlGaN/GaN structures with GaAs-Au grating are discussed using Gsolver software.
In the context of the optical properties of GaN, we have calculated the free-carrier absorption coefficient with strong longitudinal-optical (LO) phonon-plasmon interaction. We took several mechanisms into account, which assist in the photon absorption process. Computations are performed for doped alfa-GaN and beta-GaN at different mid-IR (infra red) wavelengths and doping concentrations.
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