Well-width Compensation of the Polarization Field in Polar ZnO/MgZnO Triple-Barrier Resonant Tunneling Diodes Benchmarked Against GaN/AlN
DOI:
https://doi.org/10.66514/ssst34-2-117-139Keywords:
resonant tunnelling, polarization, GaN/AlN, ZnO/MgZnO, triple barrierAbstract
Built-in polarization fields tilt the barriers of polar resonant tunneling structures and detune the coupled wells of triple barriers. We modeled GaN/AlN and ZnO/Mg0.2Zn0.8O double and triple barriers using scattering-matrix transmission, polarization electrostatics with contact accumulation and depletion, injection from the emitter two-dimensional electron gas (2DEG) and area-conserving dephasing. For measured Ga-polar GaN/AlN diodes, the model reproduces the reverse level shift and collector barrier within 9% but overestimates the forward level shift by 36%. Without 2DEG injection the current is about 300 times too low; with it, a barrier one AlN monolayer thinner than nominal brings the model close to the measured peak current and a 10 fs dephasing time reproduces the measured peak-to-valley current ratio (PVCR). In polar ZnO/MgZnO triple barriers the well offset vanishes at zero bias for a 1.5 nm middle barrier or a second well widened from 3 to 3.82 nm, but that width aligns the wells only where almost no current flows. To place the first negative differential resistance (NDR) between 0.05 and 0.15 V, the polar second well must be 0.94–1.02 nm wider than the non-polar one at the sourced polarization contrast, a shift that grows by 0.066–0.077 nm per mC m-2 of contrast and barely changes between dephasing times of 33 and 10 fs. Strong dephasing lowers the PVCR of the polar triple barrier to 1.3–1.9, against 5.8–8.0 for the non-polar reference, so interface quality likely limits polar triple barriers more than non-polar ones.
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Copyright (c) 2026 Osama Bagi Aljewaw, Sulayman Mohamad Kabeer, Mohd Mustafa Awang Kechik, Mohd Hafiz Mohd Zaid, Izdihar Kamal, Muhammad Khalis Abdul Karim (Author)
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