N-polar GaN/AlN resonant tunneling diodes
N-polar GaN/AlN resonant tunneling diodes
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DOI：
10.1063/5.0022143
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发表时间：
2020-10
期刊：
影响因子：
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通讯作者：
Yongjin Cho;J. Encomendero;Shao-Ting Ho;H. Xing;D. Jena
中科院分区：
文献类型：
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作者：
Yongjin Cho;J. Encomendero;Shao-Ting Ho;H. Xing;D. Jena
采用等离子体辅助分子束外延技术在单晶N极GaN衬底上实现了N极GaN/AlN共振隧穿二极管。室温电流-电压特性显示，在正向偏置为~8V时，有一个负的微分电导(NDC)区，峰值隧穿电流为6.8µm~0.8kA/cm2~(-1)。在反向偏置下，极化感生阈值电压为~(-4)V。这些共振和阈值电压可以用与金属-极性相反的极化电场很好地解释，证实了RTDS的N-极性。当器件偏置在NDC区时，外部电路中会产生电子振荡，这证明了共振隧穿现象的健壮性。与金属极RTD不同的是，N极结构的发射区位于共振隧道腔的顶部。因此，这种器件架构开启了通过共振隧道注入将各种奇异材料与III-氮化物半导体无缝对接的可能性，为探索新的器件物理提供了一条途径。
N-polar GaN/AlN resonant tunneling diodes are realized on single-crystal N-polar GaN bulk substrate by plasma-assisted molecular beam epitaxy growth. The room-temperature current-voltage characteristics reveal a negative differential conductance (NDC) region with a peak tunneling current of 6.8$\pm$ 0.8 kA/cm$^2$ at a forward bias of ~8 V. Under reverse bias, the polarization-induced threshold voltage is measured at ~$-$4 V. These resonant and threshold voltages are well explained with the polarization field which is opposite to that of the metal-polar counterpart, confirming the N-polarity of the RTDs. When the device is biased in the NDC-region, electronic oscillations are generated in the external circuit, attesting to the robustness of the resonant tunneling phenomenon. In contrast to metal-polar RTDs, N-polar structures have the emitter on the top of the resonant tunneling cavity. As a consequence, this device architecture opens up the possibility of seamlessly interfacing$-$via resonant tunneling injection$-$a wide range of exotic materials with III-nitride semiconductors, providing a route to explore new device physics.