Nanoporous InGaN of high In composition prepared by KOH electrochemical etching

Radzali, Rosfariza; Zainal, N.; Yam, F.K.; Hassan, Z.

doi:10.1016/j.mssp.2013.07.035

Cited by 13 publications

(6 citation statements)

References 35 publications

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“…This results in a limited pore depth, corresponding to the absorption length of the incident light. It has been reported that increasing etch time increases the porosity of these InGaN layers [71] and similar work has been done for InAlGaN, showing an increase in surface pore density with increasing etch time under PECE in KOH [73]. Comparing to results with GaN, this may suggest that this etching is occurring in a low-potential, pre-breakdown regime [31].…”

Section: Porous Nitrides Other Than Gansupporting

confidence: 58%

“…This uses a difference in bandgap to select which layers to etch. All the work we could find in the literature to form bulk porous material from In containing nitrides through anodization came from one group and uses both HF and KOH based electrolytes [70,71] and explores the influence of the light source, finding that anodization without illumination produced etching only at grain boundaries and other inhomogeneities, whereas incident light allows the formation of surface pores [72]. This results in a limited pore depth, corresponding to the absorption length of the incident light.…”

Section: Porous Nitrides Other Than Ganmentioning

confidence: 99%

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Porous nitride semiconductors reviewed

Griffin

Oliver

2020

J. Phys. D: Appl. Phys.

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Porous nitride semiconductors are a fast-developing area of study, which open up a wide range of new properties and applications, including strain free optical reflectors, chemical sensors and as a pathway to device lift-off. This article reviews the current progress in porous nitrides formed through electrochemical and photoelectrochemical methods. Using a simple electrochemical cell, pores are formed by injecting holes into the surface layer in order to oxidise the material into a soluble form and releasing nitrogen gas. The process is controlled principally by the electric field that drives the injection of holes and hence the applied potential and doping density are the key parameters for controlling pore morphology, along with how and whether illumination is used. We describe the mechanisms responsible for this process in detail and outline the trends for changing pore size and pore shape. For example, larger applied potential creates a larger electric field and hence larger pores. These methods have been used to produce a wide variety of different structures. We present a layered porous structure created by the modulation of the applied potential. Alternatively, layered structures can be produced by growing alternate doped and non-intentionally doped layers. Electrochemical etching can then create pores only in the doped layers, as they are conductive. This process can be performed by etching laterally through access trenches that expose the doped material or through the etching of dislocations to create nanopipes that allow subsurface porosity to form. This process requires no prior processing steps. We combine this method with patterning of surface protective layers to influence where the resulting pores grow. Based on these various fabrication processes, significant progress has been made towards applications of porous GaN across optoelectronics, sensing and for improving material quality.

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Section: Porous Nitrides Other Than Gansupporting

confidence: 58%

Section: Porous Nitrides Other Than Ganmentioning

confidence: 99%

Porous nitride semiconductors reviewed

Griffin

Oliver

2020

J. Phys. D: Appl. Phys.

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show abstract

“…However, dry etching technique could induce surface damage and lack of the desired selectivity for the morphology, dopant and composition (Liu et al, 2003). Meanwhile, wet etching technique such as photoelectrochemical etching is the most commonly used technique, feasibly cost-effective, has a high etching rate as well as good selectivity for most materials (Radzali et al, 2013(Radzali et al, , 2015. By applying wet etching technique, the porosity and pore diameter can be controlled by changing the etching parameter such as applied current density, etching time and electrolyte used (Fuguo et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Crystal orientation dependence of alternating current photo-assisted (ACPEC) porous silicon for potential optoelectronic application

Rahim

Mustakim

Razali

et al. 2019

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Purpose Porous silicon (PS) was successfully fabricated using an alternating current photo-assisted electrochemical etching (ACPEC) technique. This study aims to compare the effect of different crystal orientation of Si n(100) and n(111) on the structural and optical characteristics of the PS. Design/methodology/approach PS was fabricated using ACPEC etching with a current density of J = 10 mA/cm2 and etching time of 30 min. The PS samples denoted by PS100 and PS111 were etched using HF-based solution under the illumination of an incandescent white light. Findings FESEM images showed that the porous structure of PS100 was a uniform circular shape with higher density and porosity than PS111. In addition, the AFM indicated that the surface roughness of porous n(100) was less than porous n(111). Raman spectra of the PS samples showed a stronger peak with FWHM of 4.211 cm−1 and redshift of 1.093 cm−1. High resolution X-ray diffraction revealed cubic Si phases in the PS samples with tensile strain for porous n(100) and compressive strain for porous n(111). Photoluminescence observation of porous n(100) and porous n(111) displayed significant visible emissions at 651.97 nm (Eg = 190eV) and 640.89 nm (Eg = 1.93 eV) which was because of the nano-structure size of silicon through the quantum confinement effect. The size of Si nanostructures was approximately 8 nm from a quantized state effective mass theory. Originality/value The work presented crystal orientation dependence of Si n(100) and n(111) for the formation of uniform and denser PS using new ACPEC technique for potential visible optoelectronic application. The ACPEC technique has effectively formed good structural and optical characteristics of PS.

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“…Several crosssection line scans and the vertical distance were measured and the obtained value of the pore depth was averaged. A similar method has been used by other researchers to estimate the average pore depth of porous samples (Hou et al, 2001;Sohimee et al, 2018;Almanza-Workman et al, 2003;Razali et al, 2019;Radzali et al, 2013Radzali et al, , 2014Rahim et al, 2020).…”

Section: Atomic Force Microscopymentioning

confidence: 99%

Influence of different etching methods on the structural properties of porous silicon

Zulkifli

Radzali

Rahim

et al. 2022

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Purpose Porous silicon (Si) was fabricated by using three different wet etching methods, namely, direct current photo-assisted electrochemical (DCPEC), alternating CPEC (ACPEC) and two-step ACPEC etching. This study aims to investigate the structural properties of porous structures formed by using these etching methods and to identify which etching method works best. Design/methodology/approach Si n(100) was used to fabricate porous Si using three different etching methods (DCPEC, ACPEC and two-step ACPEC). All the samples were etched with the same current density and etching duration. The samples were etched by using hydrofluoric acid-based electrolytes under the illumination of an incandescent lamp. Findings Field emission scanning electron microscopy (FESEM) images showed that porous Si etched using the two-step ACPEC method has a higher porosity and density than porous Si etched using DCPEC and ACPEC. The atomic force microscopy results supported the FESEM results showing that porous Si etched using the two-step ACPEC method has the highest surface roughness relative to the samples produced using the other two methods. High resolution X-ray diffraction revealed that porous Si produced through two-step ACPEC has the highest peak intensity out of the three porous Si samples suggesting an improvement in pore uniformity with a better crystalline quality. Originality/value Two-step ACPEC method is a fairly new etching method and many of its fundamental properties are yet to be established. This work presents a comparison of the effect of these three different etching methods on the structural properties of Si. The results obtained indicated that the two-step ACPEC method produced an etched sample with a higher porosity, pore density, surface roughness, improvement in uniformity of pores and better crystalline quality than the other etching methods.

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Nanoporous InGaN of high In composition prepared by KOH electrochemical etching

Cited by 13 publications

References 35 publications

Porous nitride semiconductors reviewed

Porous nitride semiconductors reviewed

Crystal orientation dependence of alternating current photo-assisted (ACPEC) porous silicon for potential optoelectronic application

Influence of different etching methods on the structural properties of porous silicon

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