Modulation of the two-dimensional electron gas channel in flexible AlGaN/GaN high-electron-mobility transistors by mechanical bending

Weijie Wang, Jie Chen, James Spencer Lundh, Shahab Shervin, Seung Kyu Oh, Sara Pouladi, Zhoulyu Rao, Ja Yeon Kim, Min Ki Kwon, Xiaohang Li, Sukwon Choi, Jae Hyun Ryou

Research output: Contribution to journalArticle

Abstract

We investigate the effect of strain on the two-dimensional electron gas (2DEG) channel in a flexible Al0.25Ga0.75N/GaN high-electron-mobility transistor (HEMT) by mechanical bending to prove the concept of active polarization engineering to create multifunctional electronic and photonic devices made of flexible group III-nitride thin films. The flexible HEMTs are fabricated by a layer-transfer process and integrated with a 150-μm-thick Cu film. The strain values are estimated from high-resolution x-ray diffraction and Raman spectroscopy in 4-cm bend-down and -4-cm bend-up test conditions. The strain-induced piezoelectric polarization can alter the charge density of the 2DEG in the channel at the AlGaN/GaN interface and thus modify the output characteristics of the flexible HEMTs. Accordingly, output characteristics show an increase in output current by 3.4% in the bend-down condition and a decrease by 4.3% in the bend-up condition. Transfer characteristics show a shift of threshold voltage, which also supports the 2DEG channel modulation during bending. Computational simulation based on the same structure confirms the same current modulation effect and threshold voltage shift. Furthermore, the electrical characteristics of the flexible HEMTs show a repeatable dependence on the strain effect, which offers potential for electro-mechanical device applications.

Original languageEnglish (US)
Article number123501
JournalApplied Physics Letters
Volume116
Issue number12
DOIs
StatePublished - Mar 23 2020

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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    Wang, W., Chen, J., Lundh, J. S., Shervin, S., Oh, S. K., Pouladi, S., Rao, Z., Kim, J. Y., Kwon, M. K., Li, X., Choi, S., & Ryou, J. H. (2020). Modulation of the two-dimensional electron gas channel in flexible AlGaN/GaN high-electron-mobility transistors by mechanical bending. Applied Physics Letters, 116(12), [123501]. https://doi.org/10.1063/1.5142546