Asymmetrical current conduction across a 50 A thick aluminium gallium nitride polarisation barrier

2006 ◽  
Vol 1 (2) ◽  
pp. 112
Author(s):  
C.J. Praharaj ◽  
J. Hwang ◽  
L.F. Eastman
Keyword(s):  
Gallium Nitride ◽  
Aluminium Gallium Nitride ◽  
Current Conduction

Variational Calculations of Donor Binding Energy in Rectangular Wurtzite Aluminium Gallium Nitride / Gallium Nitride Quantum Wires

2007 ◽  
Vol 1040 ◽  
Author(s):  
Choudhury Jayant Praharaj
Keyword(s):  
Gallium Nitride ◽  
Binding Energy ◽  
Electric Fields ◽  
Quantum Wire ◽  
Quantum Wires ◽  
Potential Profile ◽  
Nitride Semiconductors ◽  
Aluminium Gallium Nitride ◽  
Donor Binding Energy ◽  
Variational Calculations

AbstractWe present variational calculations of donor binding energy in rectangular wurtzite aluminium gallium nitride / gallium nitride quantum wires. We explicitly take into account the effect of spontaneous and piezoelectric polarization on the energy levels of donors in quantum wires. Wurtzite structure nitride semiconductors have spontaneous polarization even in the absence of externally applied electric fields. They also have large piezoelectric polarization when grown as pseudomorphic layers. The magnitude of both polarization components is of the order of 1013 electrons per cm2, and has a non-trivial effect on the potential profile seen by electrons. Due to the large built-in electric fields resulting from the polarization discontinuities at heterojunctions, the binding energies of donors is a strong function of the position inside the quantum wire. The potential profile in the 0001 direction can vary by as much as 1.5eV due to polarization effects for vertical dimensions of the quantum wire up to 20 angstroms. The probability density of electrons tends to concentrate near the minimum of the conduction band profile in the 0001 direction. Donors located close to this minimum tend to have a larger concentration of electron density compared to those located closer to the maximum. As a consequence, the binding energy of the former are higher compared to the latter. We use Lorentzian variational wavefunctions to calculate the binding energy as a function of donor position. The confinement potential enhances the binding by a factor of about 3 compared to donors in bulk nitride semiconductors, from about 30 meV to about 90 meV. The variation of binding energy with position is calculated to be more than 50% for typical compositions of the quantum wire regions. Our calculations will be useful for understanding device applications involving n-type doped nitride semiconductor quantum wires.

scholarly journals Refractive Index of Heavily Germanium-Doped Gallium Nitride Measured by Spectral Reflectometry and Ellipsometry

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7364
Author(s):  
Dario Schiavon ◽  
Robert Mroczyński ◽  
Anna Kafar ◽  
Grzegorz Kamler ◽  
Iryna Levchenko ◽  
...  
Keyword(s):  
Refractive Index ◽  
Gallium Nitride ◽  
Production Process ◽  
Laser Diodes ◽  
Index Of Refraction ◽  
Aluminium Gallium Nitride ◽  
Process Yield ◽  
Index Contrast ◽  
Cladding Layers ◽  
Lattice Matched

Gallium nitride (GaN) doped with germanium at a level of 1020 cm−3 is proposed as a viable material for cladding layers in blue- and green-emitting laser diodes. Spectral reflectometry and ellipsometry are used to provide evidence of a reduced index of refraction in such layers. The refractive-index contrast to undoped GaN is about 0.990, which is comparable to undoped aluminium gallium nitride (AlGaN) with an aluminium composition of 6%. Germanium-doped GaN layers are lattice-matched to native GaN substrates; therefore, they introduce no strain, cracks, and wafer bowing. Their use, in place of strained AlGaN layers, will enable significant improvements to the production process yield.

scholarly journals The Effects of Piezoelectricity Matrix Constants on the Charge of a Thin Membrane

2017 ◽  
Vol 67 (2) ◽  
pp. 61-68
Author(s):  
Tomáš Kováč ◽  
František Horvát ◽  
Branislav Hučko ◽  
Roland Jančo ◽  
Miloš Musil
Keyword(s):  
Gallium Nitride ◽  
Numerical Analysis ◽  
Cross Section ◽  
Electric Charge ◽  
Circular Cross Section ◽  
Thin Membrane ◽  
Aluminium Gallium Nitride ◽  
Matrix Properties ◽  
The Matrix

AbstractThis article is devoted to the comparison of the influence of the piezoelectric matrix properties on the magnitude of the resulting charge when a thin piezoelectric membrane of circular cross section, made from aluminium gallium nitride (Al-GaN), is loaded. The size of change of the electric charge was determined by the numerical analysis and the by the change of the properties of the piezoelectric matrix. The matrix constants were obtained from various sources introduced in world databases.

Aluminium Gallium Nitride (AlGaN)/Gallium Nitride (GaN)/Boron Gallium Nitride (BGaN) High Electron Mobility Transistors (HEMT): From Normally-On to Normally-Off Transistor

2020 ◽  
Vol 18 (5) ◽  
pp. 366-370
Author(s):  
Wafa Maati ◽  
Abdelkader Hamdoune
Keyword(s):  
Gallium Nitride ◽  
Threshold Voltage ◽  
High Electron Mobility Transistors ◽  
Physical Parameters ◽  
High Electron ◽  
Aluminium Gallium Nitride ◽  
High Electron Mobility ◽  
Gan Hemt ◽  
Electron Mobility Transistors ◽  
X Band

In this paper, using the simulator TCAD SILVACO, the physical parameters to pass from a normallyon to a normally-off AlGaN/GaN HEMT with a BGaN back-barrier, was studied. With n-doped donor layer at 1 × 1016 cm–3, as a results we obtain a threshold voltage of 0.509 V normally-off AlGaN/GaN HEMT. The first transistor is able to operate in high power in better way; the second one is efficient for weak signals up to the X-band, and it has the advantage of being normally-off.

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