Deconvolution of the Potential and Time Dependence of Electrochemical Porous Semiconductor Formation

Quill, Nathan; O’Dwyer, Colm; Lynch, Robert P.; Buckley, D. H.

doi:10.1149/1.3120709

Cited by 11 publications

(22 citation statements)

References 23 publications

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“…This reflects the initial rapid increase in the density of pits which is arrested as domains merge into a continuous porous layer. [30][31][32][33][34][35][36][37][38][39][40] The separation of the pits along α is slightly larger than along β at all potentials. Presumably this asymmetry is due to the domain shape and the propagation of the initial primary pores (as shown in Fig.…”

Section: Side-to-basementioning

confidence: 84%

“…When semiconducting materials are anodized, localized etching can occur leading to selective removal of material such that the remaining material forms a skeletal structure that encompasses a network of pores. In such a manner, Si, [8][9][10][11][12][13][14][15][16][17] SiC, [18][19][20] Ge, [21][22][23] Ge/Si alloys, 24 and various III-V compounds [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] (including InP) [27][28][29][30][31][32][33][34][35][36][37][38][39][40] can be made porous.…”

mentioning

confidence: 99%

“…Our group has reported [30][31][32][33][34][35][36][37][38][39][40] the development of nanoporosity in highly doped (> 10 18 cm −3 ) n-InP anodized in > 1.2 mol dm −3 KOH and the first observation of the formation of domains of pores 40 beneath a thin layer of dense InP. 34 Interestingly, chemical etching of pore walls is not observed to take place during anodization in high molarity KOH (> 2.5 mol dm −3 ); all significant etching occurs electrochemically near the pore tips, resulting in pores of uniform diameters of less than 50 nm.…”

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confidence: 99%

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Pore Propagation Directions and Nanoporous Domain Shape in n-InP Anodized in KOH

Lynch

O’Dwyer

Quill

et al. 2013

J. Electrochem. Soc.

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Pore propagation during anodization of (100) n-InP electrodes in aqueous KOH was studied in detail by scanning and transmission electron microscopy (SEM and TEM). Pores emanating from surface pits propagate along the 〈111〉A crystallographic directions to form, in the early stages of anodization, porous domains with the shape of a tetrahedron truncated symmetrically through its center by a plane parallel to the surface of the electrode. This was confirmed by comparing the predictions of a detailed model of pore propagation with SEM and TEM observations. The model showed in detail how 〈111〉A pore propagation leads to domains with the shape of a tetrahedron truncated by a (100) plane. Observed cross sections corresponded in detail and with good precision to those predicted by the model. SEM and TEM showed that cross sections were trapezoidal and triangular, respectively, in the two cleavage planes of the wafer, and TEM showed that they were rectangular parallel to the surface plane, as predicted. Aspect ratios and angles calculated from observed cross sections were in good agreement with predicted values. The pore patterns observed were also in good agreement with those predicted and SEM observations of the surface further confirmed details of the model.

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Section: Side-to-basementioning

confidence: 84%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Pore Propagation Directions and Nanoporous Domain Shape in n-InP Anodized in KOH

Lynch

O’Dwyer

Quill

et al. 2013

J. Electrochem. Soc.

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“…[2][3][4][5][6] This is followed by some examples of research on lithium batteries and compound semiconductors at Bell Laboratories [7][8][9][10][11][12][13][14][15][16][17][18] beginning in 1979. I then discuss some of our work at the University of Limerick on electrochemical etching and nanopore formation on III-V semiconductors, [19][20][21][22][23][24][25][26][27][28][29][30] a particularly appropriate topic for this presentation in view of Professor Gerischer's 31 extensive pioneering contributions to semiconductor electrochemistry. Another topic on which I have worked is electrodeposition of copper metallization.…”

Section: Introductionmentioning

confidence: 99%

(Europe Section Heinz Gerischer Award) The Long Reach of Electrochemistry: Semiconductors, Metallization and Energy Storage

Buckley¹

2022

ECS Trans.

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Research in several different areas over the past half-century is briefly reviewed with some discussion on the evolution of equipment and techniques. Examples from our work on oxygen evolution on ruthenium and iridium and electrochromism in anodic iridium oxides in the 1970s and on lithium batteries in the 1980s are discussed. Topics in the science and technology of compound semiconductors range from epitaxial crystal growth to electrochemistry and nanopore formation. Some results are presented on electrodeposition of copper metallization including in-situ stress measurements and atomic force microscopy during deposition, and spontaneous morphology changes during room-temperature aging. Electrochemical kinetics of vanadium redox reactions on carbon electrodes is discussed as well as state-of-charge monitoring and thermal stability of the positive electrode in vanadium flow batteries.

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“…1,2,38,43,44 We have previously shown that anodization of an n-InP electrode in >2 mol dm −3 KOH results in the formation of a nanoporous InP layer 3,[48][49][50][51] of finite thickness. [52][53][54][55][56] Further investigation showed that the porous region is capped by a thin layer (20-40 nm, depending on the conditions) close to the surface that appears to be unmodified. The fact that a porous region can form within the substrate by electrochemical oxidation despite this dense InP layer is explained by the presence of a relatively low areal density (typically ∼10 7 cm −2 ) of localized channels through the layer.…”

mentioning

confidence: 99%

Anodic Formation of Nanoporous Indium Phosphide in KOH Electrolytes: Effects of Temperature and Concentration

Quill

Buckley

O’Dwyer

et al. 2019

J. Electrochem. Soc.

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Anodization of n-InP electrodes was carried out over a range of temperatures and KOH concentrations. Scanning electron microscopy showed <111>A aligned pore growth with pore width decreasing as the temperature was increased. This variation is explained in terms of the relative rates of electrochemical reaction and hole diffusion and supports the three-step model proposed earlier. As temperature is increased, both the areal density and width of surface pits decrease resulting in a large increase in the current density through the pits. This explains an observed decrease in porous layer thickness: pits sustain mass transport at the necessary rate for a shorter time before precipitation of etch products blocks the pores. As the concentration of KOH is increased, both pore width and layer thickness decrease to minima at ∼9 mol dm −3 after which they again increase. This variation of pore width is also explained by the three-step model and the variation in layer thickness is explained by mass transport effects. Layer porosity follows a similar trend to pore width, further supporting the three-step model. A transition from porous layer formation to planar etching is observed below 2 mol dm −3 KOH, and this is also explained by the three-step model.

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Deconvolution of the Potential and Time Dependence of Electrochemical Porous Semiconductor Formation

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Cited by 11 publications

References 23 publications

Pore Propagation Directions and Nanoporous Domain Shape in n-InP Anodized in KOH

Pore Propagation Directions and Nanoporous Domain Shape in n-InP Anodized in KOH

(Europe Section Heinz Gerischer Award) The Long Reach of Electrochemistry: Semiconductors, Metallization and Energy Storage

Anodic Formation of Nanoporous Indium Phosphide in KOH Electrolytes: Effects of Temperature and Concentration

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