Bipolar Properties of AlGaN/GaN/AlGaN Double Heterostructures
The effects of Al-content in AlGaN buffer(0-0.08)and GaN channel(20,50 and 80 nm)on the energy-band and carrier distribution of AlGaN/GaN/AlGaN double heterostructures are investigated by one-dimensional Schrodinger-Poisson self-consistent simulations.As the Al-content of the buffer increases,the potential barrier at the back of the channel is effectively raised,thus improving the 2DEG confinement.As the thickness of the GaN channel increases,the barrier height at the GaN channel/AlGaN buffer interface(bottom interface)increases.When the channel thickness reaches 50 nm,the heterostructure induces 2DHG near the bottom interface at an Al-content of 0.08 for the buffer,appearing"bipolar characteristic".Once the 2DHG is formed,the continued increase in the Al-content of the buffer leads to a higher density of 2DHG,while the effects on the energy-band,2DEG confinement and 2DEG density become insignificant.
AlGaN/GaN/AlGaNtwo-dimension electron gasAlGaN buffertwo-dimension hole gas
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