Surface Studies on HgCdTe Using Non-aqueous Iodine-Based Polishing Solution

Nokhwal, Radheshyam; Srivastav, Vanya; Goyal, Anshu; Sharma, B. L.; Hashmi, S.A.; Sharma, R. K.

doi:10.1007/s11664-017-5764-6

Cited by 14 publications

(6 citation statements)

References 28 publications

(41 reference statements)

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“…The etching process in our case occurs as a result of a redox reaction between the (Hg,Cd)Te surface and a solution of KI: I 2 : HBr: H 2 O. The following reactions occur during the etching process [20,26]: ). Telluride (Te 2− ) from the semiconductor lattice is oxidized with either iodine or triiodide (I 2 and I 3 are present in equilibrium in the solution: KI + I 2 Ç K + + I 3 − ) to Te 0 to commence the reaction.…”

Section: Resultsmentioning

confidence: 97%

Realization of smooth side profile using diffusion-controlled wet chemical etching for HgTe/(Hg,Cd)Te heterostructures

et al. 2023

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We utilize a diffusion-controlled wet chemical etching technique to fabricate microstructures from two-dimensional HgTe/(Hg,Cd)Te-based topological insulators. For this purpose, we employ a KI:I2:HBr:H2O-based etchant. Investigation of the side profile of the etched heterostructure reveals that HgTe quantum wells protrude from the layer stack as a result of the different etch rates of the layers. This constraint poses challenges for the study of the transport properties of edge channels in HgTe quantum wells. In order to achieve a smoother side profile, we develop a novel approach to the etching process involving the incorporation of a sacrificial design element in the etch mask. This limits the flow of charge carriers to the ions in the electrolyte during the etching process. The simplicity of the method coupled with the promising results achieved thereby should make it possible for the new approach introduced here to be applied to other semiconductor heterostructures.

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Section: Resultsmentioning

confidence: 97%

Realization of smooth side profile using diffusion-controlled wet chemical etching for HgTe/(Hg,Cd)Te heterostructures

et al. 2023

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“…Hg 1−x Cd x Te (x∼0.29) epitaxial films grown by VDLPE (vertical dipping liquid phase epitaxy) process [20] on lattice matched (111) B (Te face) surface of CdZnTe substrates were used in this work. Prior to indentation, the films were polished by 60 nm alumina powder initially to remove about a 2 μm surface layer followed by CMP on soft pad using iodine based solution developed previously at SSPL [21]. This process yields a smooth surface with a minimal surface damage.…”

Section: Methodsmentioning

confidence: 99%

Cyclic nanoindentation studies of HgCdTe epitaxial films

Sharma

Saxena

et al. 2020

Mater. Res. Express

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Hg 1−x Cd x Te (x∼0.29) epitaxial films have been subjected to cyclic nanoindentation using spherical indenter from tribological aspects related to the development of polishing process for preparing defect free surface. Different loading/unloading rates of 0.5, 1 and the 4 mNs −1 with a peak load of 10 mN were used for 10 nanoindentation cycles. An open jaw shape was observed in the load-displacement curve for loading/unloading rate of 0.5 mNs −1 , while hysteresis loops were observed for 1 and 4 mNs −1 loading/unloading rates. This phenomenon is explained in light of the regimes of elastic/ anelastic deformation and smooth plastic flow. Pop-in during first loading cycle was observed at loading/unloading rates of 1 and 4 mNs −1 , which was attributed to elasto-plastic transition. Multiple pop-in events of low extent were also found in the form of serrations in load-displacement curves for loading/unloading rates of 0.5 and 1 mNs −1 . Based on these observations, the maximum load and minimum loading rate during polishing process for this material has been suggested. The mechanical properties of these films, such as contact stiffness and hardness have been extracted for different loading/unloading rates. The effect of indenter geometry on deformation behaviour using Berkovich indenter is also reported.

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“…The (111) Te face CdZnTe single-crystal substrate (25 mm X 25 mm, 1200 µm thickness) was used for the nanoindentation studies. Prior to nanoindentation, the substrate was powder polished by 60 nm Al 2 O 3 powder followed by chemo-mechanical polishing with iodine-based solution 14 . The average surface roughness was found to be 3 nm after chemomechanical polishing using Agilent Technologies 6500 AFM as shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

Cathodoluminescence Studies of Nanoindented CdZnTe Single Crystal Substrates for Analysis of Residual Stresses and Deformation Behaviour

et al. 2020

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Nanoindentation-induced residual stresses were analysed on (111) Te face CdZnTe single-crystal substrates in this study. CdZnTe substrates were subjected to nanoindentation using cube corner indenter geometry with a peak load of 10 mN. Loading rates of 1 mN/s and 5 mN/s were used in the experiments, with a holding time of 10 s at peak load. Residual stresses on the indented region were analysed from load-displacement curves and explained using dislocation generation and elastic recovery mechanisms. Residual stresses were found to be of compressive type, just on the indented surface. The slip lines along the slip directions of this material were clearly visible in the FE-SEM images of the indents. Indents and surrounding surfaces were characterized using the Cathodoluminescence (CL) technique. CL mapping of the indented surface revealed the dislocation generation and their propagation behaviour just beneath the indenter as well as in the surrounding surfaces. The dislocations act as non-radiative recombination centres and quench the CL intensity locally. Dark lines were explained as the presence of dislocations in the material. CL mapping analysis shows that both the rosette glide and tetrahedral glide of dislocations are the primary deformation mechanisms present in CdZnTe. A rosette structure was observed in the CL mapping. CL spectra at 300 K of un-deformed CdZnTe show a peak at 810 nm wavelength, which corresponds to near-band-edge emission. After indentation, the CL spectra show the peak intensity at 814 nm and 823 nm wavelengths at the edge of the indents created with a loading rate of 1 mN/s and 5 mN/s, respectively. These peak shifts from 810 nm were attributed to the tensile residual stresses present in the indented material.

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Surface Studies on HgCdTe Using Non-aqueous Iodine-Based Polishing Solution

Cited by 14 publications

References 28 publications

Realization of smooth side profile using diffusion-controlled wet chemical etching for HgTe/(Hg,Cd)Te heterostructures

Realization of smooth side profile using diffusion-controlled wet chemical etching for HgTe/(Hg,Cd)Te heterostructures

Cyclic nanoindentation studies of HgCdTe epitaxial films

Cathodoluminescence Studies of Nanoindented CdZnTe Single Crystal Substrates for Analysis of Residual Stresses and Deformation Behaviour

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