Au-Capped GaAs Nanopillar Arrays Fabricated by Metal-Assisted Chemical Etching

Asoh, Hidetaka; Imai, Ryota; Hashimoto, Hideki

doi:10.1186/s11671-017-2219-1

Cited by 8 publications

(8 citation statements)

References 25 publications

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“…So far, only few attempts have been made to extend wet etching processes to structure the surface of III–V semiconductors. The MACE of GaAs was demonstrated in conjunction with thermal evaporation, or lithographic patterning of the metal catalyst − by photolithography, nanoimprint lithography, and microsphere self-assembly, whereas the use of catalyst nanoparticles was shown using Au films evaporated on the GaAs surface and subsequently treated at high temperature . Thermal treatment can induce arsenic vacancies and lead to catalyst diffusion on the GaAs surface.…”

Section: Introductionmentioning

confidence: 99%

Black GaAs by Metal-Assisted Chemical Etching

Lova

Robbiano

Cacialli

et al. 2018

ACS Appl. Mater. Interfaces

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Large area surface microstructuring is commonly employed to suppress light reflection and enhance light absorption in silicon photovoltaic devices, photodetectors, and image sensors. To date, however, there are no simple means to control the surface roughness of III-V semiconductors by chemical processes similar to the metal-assisted chemical etching of black Si. Here, we demonstrate the anisotropic metal-assisted chemical etching of GaAs wafers exploiting the lower etching rate of the monoatomic Ga<111> and <311> planes. By studying the dependence of this process on different crystal orientations, we propose a qualitative reaction mechanism responsible for the self-limiting anisotropic etching and show that the reflectance of the roughened surface of black GaAs reduces up to ∼50 times compared to polished wafers, nearly doubling its absorption. This method provides a new, simple, and scalable way to enhance light absorption and power conversion efficiency of GaAs solar cells and photodetectors.

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Section: Introductionmentioning

confidence: 99%

Black GaAs by Metal-Assisted Chemical Etching

Lova

Robbiano

Cacialli

et al. 2018

ACS Appl. Mater. Interfaces

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“…The MacEtch and I-MacEtch processes were detailed and formalized in 2000 and 2015,, respectively. These techniques are powerful alternatives for the fabrication of micro- and nano-structures that have been utilized throughout many fields, such as energy storage, photonics, , nanoelectronics, , photovoltaics, and optoelectronics. , Although much of the MacEtch work has predominantly been related to Si, − binary III–V compound semiconductors, including GaAs, ,− InP, ,, GaP, and GaN, , have been explored in recent years, and ternary III–V alloys, including InGaAs and InGaP, have been reported in the past year.…”

Section: Introductionmentioning

confidence: 99%

Ordered Al_xGa_1–xAs Nanopillar Arrays via Inverse Metal-Assisted Chemical Etching

Wilhelm

Wang

Baboli

et al. 2018

ACS Appl. Mater. Interfaces

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The ternary III-V semiconductor compound, Al GaAs, is an important material that serves a central role within a variety of nanoelectronic, optoelectronic, and photovoltaic devices. With all of its uses, the material itself poses a host of fabrication difficulties stemming from conventional top-down processing, including standard wet-chemical etching and reactive-ion etching (RIE). Metal-assisted chemical etching (MacEtch) techniques provide low-cost and benchtop methods that combine many of the advantages of RIE and wet-chemical etching, without being hindered by many of their disadvantages. Here, inverse-progression MacEtch (I-MacEtch) of Au-patterned Al GaAs is demonstrated for the first time and is exploited for the generation of vertical and ordered nanopillar arrays. The etching solution employed here consists of citric acid (CHO) and hydrogen peroxide (HO). The I-MacEtch evolution is tracked in time for Al GaAs samples with compositions defined by x = 0.55, x = 0.60, and x = 0.70. The vertical and lateral etch rates (VER and LER, respectively) are shown to be tunable with Al fraction and temperature of the etching solution, based on modification of catalytically injected hole distributions. Control over the VER/LER ratio is demonstrated by tailoring etch conditions for single-step fabrication of ordered AlGaAs nanopillar arrays with predefined aspect ratios. Maximum VER and LER values of ∼40 nm/min and ∼105 nm/min, respectively, are measured for AlGaAs at a process temperature of 65 °C. The I-MacEtch nanofabrication methodology outlined in this study may be utilized for the processing of many devices, including high electron mobility transistors, distributed Bragg reflectors, lasers, light-emitting diodes, and multijunction solar cells containing AlGaAs components.

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“…Recently, the MACE method was successfully applied for nanopatterning of III-V compound semiconductors. For instance, it was used to fabricate nanopillar arrays of GaAs (Asoh et al, 2017), InP (Asoh et al, 2010), GaN (Zhang et al, 2017), GaP (Kim & Oh, 2016) and InGaAs (Kong et al, 2017). This confirms the great potential of the method for a wide range of devices (Huang et al, 2011, Han et al, 2014, Banu et al, 2015.…”

Section: Introductionmentioning

confidence: 91%

Unravelling the strain relaxation processes in silicon nanowire arrays by X-ray diffraction

et al. 2019

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Investigations performed on silicon nanowires of different lengths by scanning electron microscopy revealed coalescence processes in longer nanowires. Using X‐ray diffraction (XRD), it was found that the shape of the pole figure in reciprocal space is ellipsoidal. This is the signature of lattice defects generated by the relaxation of the strain concentrated in the coalescence regions. This observation is strengthened by the deviation of the XRD peaks from Gaussianity and the appearance of the acoustic phonon mode in the Raman spectrum. It implies that bending, torsion and structural defects coexist in the longer nanowires. To separate these effects, a grazing‐incidence XRD technique was conceived which allows the nanowire to be scanned along its entire length. Both ω and ϕ rocking curves were recorded, and their shapes were used to extract the bending and torsion profiles, respectively, along the nanowire length. Dips were found in both profiles of longer nanowires, while they are absent from shorter ones, and these dips correspond to the regions where both bending and torsion relax. The energy dissipated in the nanowires, which tracks the bending and torsion profiles, has been used to estimate the emergent dislocation density in nanowire arrays.

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Au-Capped GaAs Nanopillar Arrays Fabricated by Metal-Assisted Chemical Etching

Cited by 8 publications

References 25 publications

Black GaAs by Metal-Assisted Chemical Etching

Black GaAs by Metal-Assisted Chemical Etching

Ordered Al_xGa_1–xAs Nanopillar Arrays via Inverse Metal-Assisted Chemical Etching

Unravelling the strain relaxation processes in silicon nanowire arrays by X-ray diffraction

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Au-Capped GaAs Nanopillar Arrays Fabricated by Metal-Assisted Chemical Etching

Cited by 8 publications

References 25 publications

Black GaAs by Metal-Assisted Chemical Etching

Black GaAs by Metal-Assisted Chemical Etching

Ordered AlxGa1–xAs Nanopillar Arrays via Inverse Metal-Assisted Chemical Etching

Unravelling the strain relaxation processes in silicon nanowire arrays by X-ray diffraction

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Ordered Al_xGa_1–xAs Nanopillar Arrays via Inverse Metal-Assisted Chemical Etching