Correlation of Raman and photoluminescence spectra of electrochemically prepared n-type porous GaAs

Ali, N. K.; Hashim, M.R.; Aziz, Azlan Abdul; Hassan, H. Abu

doi:10.1088/0268-1242/23/5/055016

Cited by 18 publications

(8 citation statements)

References 41 publications

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“…4, and the superposition of smaller peaks which is more representative for comparison with the results of other Raman studies performed on p-GaAs -achieved through an oxidation etching procedure [17][18][19] -rather than the published spectra of a-As. 15 For completeness, we point out that none of the peak frequencies of these vibrations align with any of the vibrations suggested for the various arsenic or gallium oxide polymorphs.…”

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confidence: 77%

Fabrication and characterisation of GaAs nanopillars using nanosphere lithography and metal assisted chemical etching

et al. 2016

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. (2016). Fabrication and characterisation of GaAs nanopillars using nanosphere lithography and metal assisted chemical etching. RSC Advances: an international journal to further the chemical sciences, 6 30468-30473.Fabrication and characterisation of GaAs nanopillars using nanosphere lithography and metal assisted chemical etching AbstractWe present a low-cost fabrication procedure for the production of nanoscale periodic GaAs nanopillar arrays, using the nanosphere lithography technique as a templating mechanism and the electrochemical metal assisted etch process (MacEtch). The room-temperature photoluminescence (PL) and Raman spectroscopic properties of the fabricated pillars are detailed, as are the structural properties (scanning electron microscopy) and fabrication process. From our PL measurements, we observe a singular GaAs emission at 1.43 eV with no indications of any blue or green emissions, but with a slight redshift due to porosity induced by the MacEtch process and characteristic of porous GaAs (p-GaAs). This is further confirmed via Raman spectroscopy, where additionally we observe the formation of an external cladding of elemental As around our nanopillar features. The optical emission is enhanced by an order magnitude (~300%) for our nanopillar sample relative to the planar unprocessed GaAs reference. We present a low-cost fabrication procedure for the production of nanoscale periodic GaAs nanopillar arrays, using the nanosphere lithography technique as a templating mechanism and the electrochemical metal assisted etch process (MacEtch). The room-temperature photoluminescence (PL) and Raman spectroscopic properties of the fabricated pillars are detailed, as are the structural properties (scanning electron microscopy) and fabrication process. From our PL measurements, we observe a singular GaAs emission at 1.43 eV with no indications of any blue or green emissions, but with a slight redshift due to porosity induced by the MacEtch process and characteristic of porous GaAs (p-GaAs). This is further confirmed via Raman spectroscopy, where additionally we observe the formation of an external cladding of elemental As around our nanopillar features. The optical emission is enhanced by an order magnitude ($300%) for our nanopillar sample relative to the planar unprocessed GaAs reference.

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confidence: 77%

Fabrication and characterisation of GaAs nanopillars using nanosphere lithography and metal assisted chemical etching

et al. 2016

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“…[36] Moreover, if etched GaAs surface is completely porous, a significantly broadened TO peak locating at 150-250 cm -1 should be identified. [37,38] However, the TO peak in Raman spectrum of GaAs nanopillar array remained sharp, indicating that the GaAs layer remained intact rather than being completely porous after MacEtch.…”

Section: Resultsmentioning

confidence: 99%

Distinct UV–Visible Responsivity Enhancement of GaAs Photodetectors via Monolithic Integration of Antireflective Nanopillar Structure and UV Absorbing IGZO Layer

Liao

Zheng

Shin

et al. 2022

Advanced Optical Materials

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characteristic with a bandgap energy of ≈1.4 eV. The bandgap energy also enables its usage in visible photodetection. [7,8] In addition, GaAs has exhibited its potentials in the ultraviolet (UV) photodetection due to the high absorption coefficient. [9,10] Nowadays, broadband UV-visible photodetectors exhibit outstanding application potentials in areas such as environment, energy, and imaging. [11] Among various semiconductor materials, GaAs is one of the best candidates for broadband UV-visible photodetection considering the suitable bandgap for visible light detection and high absorption coefficient in UV range.However, two challenges still exist in improving the UV-visible responsivity of GaAs photodetectors: 1) surface reflection loss of incident light and 2) shallow penetration depth of GaAs in UV range. The former issue can be effectively ameliorated by employing various antireflection schemes. Among them, surface texturing such as textured GaAs, [12,13] GaAs nanocones [14,15] and porous GaAs [16][17][18][19] has shown a facile and effective way to achieve a broadband antireflection, compared with a multilayered antireflection coating which requires a precise control of refractive index and thickness of individual layer. [20] Although some of these works on surface texturing demonstrated low UV-visible reflection below 5%, none of them have systematically studied an implication of the textured antireflection layer in GaAs photodetectors and their performance enhancement in a broadband UV-visible range. For example, Namiki et al. [21] fabricated GaAs nanogrooves which exhibited distinctly reduced reflectance from 400 to 1000 nm wavelength. However, this photodetector was only characterized under 532 nm visible illumination and its performance enhancement in a broadband UV-visible range was not reported. In fact, it is challenging to realize the UV performance enhancement in GaAs photodetectors due to the latter issue, i.e., the shallow penetration depth of UV light in GaAs which leads to significant loss of photocarriers by recombination. [22] The surface recombination is expected to be more severe in UV range for antireflective structures due to potential formation of more surface states as traps and recombination centers which are introduced by larger surface areas and fabrication methods such as etching. [12,23] On the other hand, Broadband ultraviolet-visible photodetection has been attracting growing research interests in fields of environment, energy, and imaging. Considering the suitable bandgap and high absorption coefficient, GaAs is one of the best candidates for ultraviolet-visible photodetection. In this work, a monolithic integration strategy of nanopillar antireflective structure and InGaZnO (IGZO) ultraviolet absorbing layer is proposed to enhance the ultraviolet-visible spectral responsivity of GaAs photodetectors. Both nanopillar topography and IGZO layer exhibit antireflective performance, leading to the enhancement of the light absorption and responsivity of the photodetectors. By the comb...

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“…32 This model was used to estimate the average size ͑or correlation length͒ L of the nanocrystals from the Raman spectrum. 33 The nanocrystallites size obtained from the best fit of generated spectra to the LO mode of experimental spectra in Fig. 5, for samples ͑a͒-͑d͒ and ͑dc͒ are 3.1, 2.8, 2.4, 3.5, and 3.8 nm, respectively.…”

Section: K10mentioning

confidence: 99%

Formation of Porous GaAs by Pulsed Current Electrochemical Anodization: SEM, XRD, Raman, and Photoluminescence Studies

Ali¹,

Hashim²,

Aziz³

et al. 2009

Electrochem. Solid-State Lett.

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Porous GaAs ͑-GaAs͒ has been fabricated using pulsed current electrochemical etching. Scanning electron microscopy ͑SEM͒ shows that the time off ͑T off ͒, time on ͑T on ͒, and cycle time ͑T͒ can promote thicker and more uniform -GaAs layers compared to those of direct current etching. Choosing suitable pulse parameters produces -GaAs layers with a thickness of 90 m and crystallite size of 2.4 nm. X-ray diffraction ͑XRD͒ shows a high degree of crystallinity of the samples. Photoluminescence ͑PL͒ spectra showed two or three PL bands besides the PL band of the single-crystalline GaAs ͑c-GaAs͒. Peak PL wavelengths were located approximately at 362, 426, and 540 nm.After the discovery of the room temperature visible photoluminescence ͑PL͒ in porous Si, 1 pore formation in III-V materials received a great deal of attention from the scientific community. Several approaches have been used to fabricate porous GaAs ͑-GaAs͒, including electrochemical anodization, spark processed porous, and laser-induced etching. 2-4 Most -GaAs reported to date have shown a certain degree of inhomogeneity with respect to morphology, surface chemistry, and PL. [5][6][7] showed that the porous layers formed in n + GaAs͑100͒ samples were uniform both laterally and vertically. The porous layers in the n-GaAs͑111͒ samples were relatively uniform, although their thickness fluctuated by as much as 20% on different parts of the wafer. Porous layers formed in n − GaAs͑100͒ were characterized by rectangular surface regions of 200 ϫ 300 m, where pores were initiated, while other parts of the surface remained unetched. Maosheng Hao et al. 8 have formed -GaAs using a two-step electrochemical anodization process, producing a high density of pores with uniform distribution in n-type GaAs. More recently, Mavi et al. 4 have fabricated GaAs nanostructure by laser-induced etching using Nd:yttrium aluminum garnet ͑ = 1.06 m͒ laser, producing nanostructure sizes controllable by changing laser parameters.Difficulty in controlling the nanoscale structure and related properties of GaAs remains as the main challenge. This obviously requires correlating the parameters of the synthesis process with the resulting nanostructure. The pulse current electrochemical approach, 9 if it attains sufficiently high controllability at the nanometer scale, seems to be a highly useful technique. In this technique, instead of using a dc current, a sequence of current pulses is used to form a porous material. Porous silicon with controlled thickness has been successfully prepared using this technique, which gives thicker and more uniform porous layers showing higher PL intensity. [10][11][12] The technique was also used to precisely control etching for processing nanodevices because the pulsed mode enables an extremely small etching rate of ϳ10 −5 nm per pulse. 13 In this work, we report on the formation of -GaAs by using the pulse current anodization technique. The main feature is the on/off cycle at fixed current density and electrolyte composition. The time when there is current, ...

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Correlation of Raman and photoluminescence spectra of electrochemically prepared n-type porous GaAs

Cited by 18 publications

References 41 publications

Fabrication and characterisation of GaAs nanopillars using nanosphere lithography and metal assisted chemical etching

Fabrication and characterisation of GaAs nanopillars using nanosphere lithography and metal assisted chemical etching

Distinct UV–Visible Responsivity Enhancement of GaAs Photodetectors via Monolithic Integration of Antireflective Nanopillar Structure and UV Absorbing IGZO Layer

Formation of Porous GaAs by Pulsed Current Electrochemical Anodization: SEM, XRD, Raman, and Photoluminescence Studies

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