Effect of crystal orientation of GaN/V2O5 core-shell nanowires on piezoelectric nanogenerators

Waseem, Aadil; Johar, Muhammad Ali; Hassan, Mostafa Afifi; Bagal, Indrajit V.; Ha, Jun‐Seok; Lee, June Key; Ryu, Sang‐Wan

doi:10.1016/j.nanoen.2019.03.075

Cited by 35 publications

(35 citation statements)

References 41 publications

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“…These properties enable PENGs to exhibit long‐term stability due to the direct integration of GaN NWs grown on the required substrate instead of growing NWs onto a bulk crystalline substrate followed by their transfer onto flexible foreign substrates that ultimately degrade the durability of the PENGs. [ 33,37 ] The direct growth of GaN NWs onto a flexible metal foil coated by a 2D material may be the optimal approach. Several metallic substrates such as tungsten, molybdenum, and titanium have been employed as host substrates for GaN NW‐growth by molecular beam epitaxy (MBE) due to their high melting temperature.…”

Section: Introductionmentioning

confidence: 99%

Highly Durable Piezoelectric Nanogenerator by Heteroepitaxy of GaN Nanowires on Cu Foil for Enhanced Output Using Ambient Actuation Sources

Johar

Waseem

Hassan

et al. 2020

Advanced Energy Materials

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Highly durable piezoelectric nanogenerators (PENGs) with high conversion efficiency and high power density are of great interest. Here, a foldable, scalable, durable, cost‐effective, sensitive, and high current output PENG developed by the direct integration of van der Waals heteroepitaxial growth of GaN nanowires (NWs) by metal‐organic chemical vapor deposition using a graphene coating on a Cu‐foil is reported where the direct growth of GaN on the metallic substrate plays a key role in achieving the high stability of the PENG. The PENG provides a durable and highly sensitive output compared to the previously reported GaN NW‐based PENGs fabricated by transferring NWs onto a foreign substrate. The reported PENG can harvest energy from a variety of ambient actuation sources such as bending, vibrations, air flow, finger pressing, foot striking, fluid flow, and normal force by weights, with the maximum piezoelectric output voltage and current density recorded as 19.7 V and 1.9 mA cm−2, respectively. Due to its high conversion efficiency, the PENG can power several LEDs and thus can be used to power electronic devices. More importantly, the PENG retains its performance after more than 4 million actuation cycles, demonstrating the potential of the design for practical applications using biomechanical and ambient actuation sources for self‐powered systems.

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Section: Introductionmentioning

confidence: 99%

Highly Durable Piezoelectric Nanogenerator by Heteroepitaxy of GaN Nanowires on Cu Foil for Enhanced Output Using Ambient Actuation Sources

Johar

Waseem

Hassan

et al. 2020

Advanced Energy Materials

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“…[1][2][3] Nanowires (NWs) are currently being studied in a variety of elds including the elds of optical, 4 electronic, 5 sensing, 6 and energy applications. [7][8][9] To fully exploit all of the potential advantages of NWs, a variety of approaches for the fabrication and characterization of multidimensional composite NWs have been used. [10][11][12] These methods provide opportunities to integrate diverse materials into hierarchical NWs and enable the optimization of the structures in terms of the materials.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional hierarchical semi-polar GaN/InGaN MQW coaxial nanowires on a patterned Si nanowire template

et al. 2020

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“…During the VLS growth mode, it is possible to control the growth direction of GaN core NWs on any substrate such as the growth of m -axial, a -axial, or c -axial NWs using the same substrate by controlling the catalyst composition. 27 , 34 …”

Section: Resultsmentioning

confidence: 99%

Epitaxial Growth of GaN Core and InGaN/GaN Multiple Quantum Well Core/Shell Nanowires on a Thermally Conductive Beryllium Oxide Substrate

et al. 2020

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Beryllium oxide (BeO) belongs to a very unique material family that exhibits the divergent properties of high thermal conductivity and high electrical resistivity. BeO has the same crystal structure as GaN, and the absolute difference in the lattice constants is less than 17%. Here, the growth of GaN nanowires (NWs) on the polycrystalline BeO substrate is reported for the first time. The NWs are grown by a vapor–liquid–solid approach using a showerhead-based metal–organic chemical vapor deposition. The growth direction of NWs is along the m -axis on all planes of the substrate, and it is confirmed by transmission electron microscopy (TEM) and selected area electron diffraction (SAED) patterns. The vertical and tilted growth of NWs is due to the different planes of the substrate such as the m -plane, a -plane, and semipolar planes and is confirmed by X-ray diffraction. Subsequently, the GaN shell and InGaN/GaN multiple quantum wells (MQWs) are coaxially grown using a vapor–solid approach in the same reactor. A very high crystal quality is verified by TEM and SAED and is also confirmed by measuring the photoluminescence. The optical emission is tuned for the entire visible spectrum by increasing the indium incorporation in InGaN quantum wells. The conformal growth of InGaN/GaN MQW shells and the defect-free nature of the structure are confirmed from spatially resolved cathodoluminescence. This study will provide a platform for researchers to grow GaN NWs on the BeO substrate for a range of optical and electrical applications.

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Effect of crystal orientation of GaN/V2O5 core-shell nanowires on piezoelectric nanogenerators

Cited by 35 publications

References 41 publications

Highly Durable Piezoelectric Nanogenerator by Heteroepitaxy of GaN Nanowires on Cu Foil for Enhanced Output Using Ambient Actuation Sources

Highly Durable Piezoelectric Nanogenerator by Heteroepitaxy of GaN Nanowires on Cu Foil for Enhanced Output Using Ambient Actuation Sources

Three-dimensional hierarchical semi-polar GaN/InGaN MQW coaxial nanowires on a patterned Si nanowire template

Epitaxial Growth of GaN Core and InGaN/GaN Multiple Quantum Well Core/Shell Nanowires on a Thermally Conductive Beryllium Oxide Substrate

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