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Abstract-Polarization effects and polarization charges on the interfaces between GaN and AlGaN in GaN/AlGaN RTD on cplane GaN substrate destroy its RT conditions. To pave the way for electron transportation through GaN/AlGaN RTD in the mode of resonant tunneling, the influence from polarization effects was analyzed and a way to restrain it on the NDR characteristic was found. Since the polarization field is along the negative C crystal orientation, while the external applied field is orthogonal to the original crystal plane, the effective polarization field was modeled and device simulations of the polarization effects in GaN/AlGaN RTDs with different initial crystal planes of GaN substrates were carried out. The results indicate that to select an initial crystal plane of GaN substrate by increasing the c-plane drift angle from 0 to /2 is very helpful to recover and enhance the RT conditions since it is capable of reducing effective polarization field, forming RT quantum state energy levels on both sides of potential barriers and improving electron transmission. Therefore, the crystal planes between { 1 0 2 2 } and a-plane are optional as the initial crystal plane of GaN substrate for related power levels of related practical applications.

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