Efficient Light Absorption by GaN Truncated Nanocones for High Performance Water Splitting Applications.

Despite the importance of gallium nitride (GaN) nanostructures for photocatalytic activity, relatively little attention has been paid to their geometrical optimization on the basis of wave optics. In this study, we present GaN truncated nanocones to provide a strategy for improving solar water splitting efficiencies, compared to the efficiency provided by the conventional geometries (i.e., flat surface, cylindrical, and cone shapes). Computational results with a finite difference time domain (FDTD) method and a rigorous coupled-wave analysis (RCWA) reveal important aspects of truncated nanocones, which effectively concentrate light in the center of the nanostructures. The introduction of nanostructures is highly recommended to address the strong light reflection of photocatalytic materials and carrier lifetime issues. To fabricate the truncated nanocones at low cost and with large-area, a dry etching method was employed with thermally dewetted metal nanoparticles, which enables controllability of desired features on a wafer scale. Experimental results exhibit that the photocurrent density of truncated nanocones is improved about three times higher compared to that of planar GaN.

[1]  Gil Ju Lee,et al.  Plasmonic Silver Nanoparticle-Impregnated Nanocomposite BiVO4 Photoanode for Plasmon-Enhanced Photocatalytic Water Splitting , 2018 .

[2]  A-Andrew D Jones,et al.  Evaluation of Nitrogen Doping of Tungsten Oxide for Photoelectrochemical Water Splitting , 2008 .

[3]  Fang Qian,et al.  Nitrogen-doped ZnO nanowire arrays for photoelectrochemical water splitting. , 2009, Nano letters.

[4]  John Rick,et al.  Using hematite for photoelectrochemical water splitting: a review of current progress and challenges. , 2016, Nanoscale horizons.

[5]  Lixia Zhao,et al.  Light Modulation and Water Splitting Enhancement Using a Composite Porous GaN Structure. , 2018, ACS applied materials & interfaces.

[6]  Karsten Bittkau,et al.  Random versus periodic: Determining light trapping of randomly textured thin film solar cells by the superposition of periodic surface textures , 2015 .

[7]  A. Fujishima,et al.  Electrochemical Photolysis of Water at a Semiconductor Electrode , 1972, Nature.

[8]  Dunjun Chen,et al.  Significant improvements in InGaN/GaN nano-photoelectrodes for hydrogen generation by structure and polarization optimization , 2016, Scientific Reports.

[9]  Tien Khee Ng,et al.  Water splitting to hydrogen over epitaxially grown InGaN nanowires on a metallic titanium/silicon template: reduced interfacial transfer resistance and improved stability to hydrogen , 2018 .

[10]  J. Ha,et al.  Enhanced solar hydrogen generation of high density, high aspect ratio, coaxial InGaN/GaN multi-quantum well nanowires , 2015 .

[11]  H. E. Bennett,et al.  Relation between Surface Roughness and Specular Reflectance at Normal Incidence , 1961 .

[12]  K. Domen,et al.  Recent advances in semiconductors for photocatalytic and photoelectrochemical water splitting. , 2014, Chemical Society reviews.

[13]  Jing Li,et al.  Hydrogen generation by solar water splitting using p-InGaN photoelectrochemical cells , 2010 .

[14]  Z. Benzarti,et al.  Study of Surface and Interface Roughness of GaN-Based Films Using Spectral Reflectance Measurements , 2015, Journal of Electronic Materials.

[15]  Jiangtian Li,et al.  Plasmon-induced photonic and energy-transfer enhancement of solar water splitting by a hematite nanorod array , 2013, Nature Communications.

[16]  G. Schrauzer,et al.  Photolysis of water and photoreduction of nitrogen on titanium dioxide , 1977 .

[17]  Lixia Zhao,et al.  GaN with Laterally Aligned Nanopores To Enhance the Water Splitting , 2017 .

[18]  K. Domen,et al.  Photocatalytic overall water splitting on gallium nitride powder , 2007 .

[19]  S. Aloni,et al.  Complete composition tunability of InGaN nanowires using a combinatorial approach. , 2007, Nature materials.

[20]  A. Mendes,et al.  Characterization of photoelectrochemical cells for water splitting by electrochemical impedance spectroscopy , 2010 .

[21]  Young Min Song,et al.  Nano‐tailoring the Surface Structure for the Monolithic High‐Performance Antireflection Polymer Film , 2010, Advanced materials.

[22]  Kazuhiko Maeda,et al.  GaN:ZnO solid solution as a photocatalyst for visible-light-driven overall water splitting. , 2005, Journal of the American Chemical Society.

[23]  Paul W. Leu,et al.  Ultrahigh-transparency, ultrahigh-haze nanograss glass with fluid-induced switchable haze , 2017 .

[24]  Yi Cui,et al.  Efficient solar-driven water splitting by nanocone BiVO4-perovskite tandem cells , 2016, Science Advances.

[25]  Michael Grätzel,et al.  Photoelectrochemical cells , 2001, Nature.

[26]  G. Borghs,et al.  Impact of Plasma-Induced Surface Damage on the Photoelectrochemical Properties of GaN Pillars Fabricated by Dry Etching , 2014 .

[27]  Fan Zhang,et al.  Water splitting by tungsten oxide prepared by atomic layer deposition and decorated with an oxygen-evolving catalyst. , 2011, Angewandte Chemie.

[28]  T. Jaramillo,et al.  Nearly Total Solar Absorption in Ultrathin Nanostructured Iron Oxide for Efficient Photoelectrochemical Water Splitting , 2014 .

[29]  Disordered submicron structures integrated on glass substrate for broadband absorption enhancement of thin-film solar cells , 2012 .

[30]  C. Jagadish,et al.  Improved photoelectrochemical performance of GaN nanopillar photoanodes , 2017, Nanotechnology.

[31]  Young Min Song,et al.  Design of highly transparent glasses with broadband antireflective subwavelength structures. , 2010, Optics express.

[32]  Tao Wang,et al.  Enhancement in solar hydrogen generation efficiency using a GaN-based nanorod structure , 2013 .

[33]  Hyuneui Lim,et al.  Improved antireflection properties of moth eye mimicking nanopillars on transparent glass: flat antireflection and color tuning. , 2012, Nanoscale.

[34]  D. Wiersma,et al.  Disordered photonic structures for light harvesting in solar cells. , 2013, Optics express.