Epitaxial Lift-Off of Flexible GaN‑Based HEMT Arrays with Performances Optimization by the Piezotronic Effect

High-electron-mobility transistors(HEMTs)are a promising device in the field of radio frequency and wireless communication.However,to unlock the full potential of HEMTs,the fabrication of large-size flexible HEMTs is required.Herein,a large-sized(>2 cm^(2))of AlGaN/AlN/GaN heterostructure-based HEMTs were successfully stripped from sapphire substrate to a flexible polyethylene terephthalate substrate by an electrochemical lift-off technique.The piezotronic effect was then induced to optimize the electron transport performance by modulating/tuning the physical properties of two-dimensional electron gas(2DEG)and phonons.The saturation current of the flexible HEMT is enhanced by 3.15%under the 0.547%tensile condition,and the thermal degradation of the HEMT was also obviously suppressed under compressive straining.The corresponding electrical performance changes and energy diagrams systematically illustrate the intrinsic mechanism.This work not only provides in-depth understanding of the piezotronic effect in tuning 2DEG and phonon properties in GaN HEMTs,but also demonstrates a low-cost method to optimize its electronic and thermal properties.

Plasmon-enhanced self-powered GaN/ZnTe core/shell nanopillar array photodetector

Nanostructure photodetectors,as the core component of optoelectronic devices,are mainly focused on the precise preparation of mixed-component nano-heterostructures and the realization of zero power consumption devices.Herein,we successfully fabricated n-GaN/p-ZnTe core/shell nanopillar array and realized self-power ultraviolet/violet photodetection.The radial heterojunction nanodevice reveals high light-dark current ratio of 104 at 0 V bias,indicating effective carriers’separation.And more,by integrating plasmonic effect,the responsivity and detectivity of the Au nanoparticles decorated device are increased from 3.85 to 148.83 mA/W and 4.45×1011 to 2.33×1012 Jones under 325 nm UV light irradiation.While the rise and the fall time are decreased 1.3 times and 6.8 times under 520 nm visible light irradiation at 0 V bias.The high photocurrent gain is derived from that the oscillating high-energy hot electrons in Au nanoparticles spontaneously inject into the ZnTe conduction band to involve the photodetection process.This work presents an effective route to prepare high-performance self-power photodetector and provides a promising blueprint to realize different functional photoelectronic devices based on core/shell nanostructure.