Growth of CdxHg1−xTe semiconductor films by electrodeposition technique

Sahu, S.N.; Sánchez, Carlos

doi:10.1016/0038-1098(90)90246-8

Cited by 8 publications

(5 citation statements)

References 8 publications

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“…EC-ALE is an attractive electrosynthetic alternative to conventional deposition methods because it is inexpensive, operates at ambient temperature and pressure, and provides precise film thickness control. This technique promises to overcome problems associated with other electrosynthetic approaches, such as the formation of highly polycrystalline deposits and interfacial interdiffusion . There are, however, a number of challenges associated with synthesizing quality thin films using upd.…”

Section: Introductionmentioning

confidence: 99%

A Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy Study of Electrochemically Grown ZnS Monolayers on Au(111)

1999

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The structure and chemical composition of electrosynthesized ZnS thin films on Au(111) substrates was studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). The films were grown by alternating underpotential deposition and oxidative adsorption cycles of S and Zn from solution precursors (electrochemical atomic layer epitaxy, EC-ALE). Oxidative adsorption of the first layer of S results in a ( × )R30° adlattice on Au(111). In the initial Zn monolayer, XPS indicates the presence of SO4 2- derived from the supporting electrolyte. The coadsorbed SO4 2- can be chemically or electrochemically displaced by H2S(aq) or HS(aq) -, leading to the formation of ZnS. Atomically resolved STM images show the ZnS/Au(111) monolayer to be 6-fold symmetric with an interatomic spacing of 0.37 ± 0.01 nm. The structure of the deposit on the micrometer scale was also investigated by STM. The first complete EC-ALE cycle results in the formation of nanocrystallites of ZnS randomly distributed across Au(111) terraces. The average diameter of the crystallites is 10 ± 5 nm, and the apparent coverage of ZnS is 0.38.

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Section: Introductionmentioning

confidence: 99%

A Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy Study of Electrochemically Grown ZnS Monolayers on Au(111)

1999

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“…Most electrosynthetic schemes, however, suffer from two decisive disadvantages. First, the deposits tend to be highly polycrystalline because nucleation and growth, adsorption/desorption phenomena, surface reconstruction, and surface diffusion typically are not under experimental control. Second, electrodeposited materials tend to be relatively impure due to the incorporation of components of the supporting electrolyte into the deposit as it forms.…”

Section: Introductionmentioning

confidence: 99%

Electrochemistry of S Adlayers at Underpotentially Deposited Cd on Au(111): Implications for the Electrosynthesis of High-Quality CdS Thin Films

et al. 1998

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We report an electrochemical, scanning probe microscopic, and Raman spectroscopic investigation of thin CdS films grown by electrochemical atomic layer epitaxy aimed at understanding the role played by the order of deposition on film quality. Using scanning tunneling microscopy (STM), we determine the atomic level structure of the first three monolayers of CdS for Cd-first films. The initial Cd underpotential deposition layer forms a stable ( 0 4 1 -2)-Au(111) adlattice in which the two unique nearest neighbor spacings are 0.33 and 0.29 nm. When H 2 S is electrolyzed at this surface at underpotential, an adlattice is produced in which the S-S interatomic spacing is 0.34 nm. The unit cell of this structure is ( 0) with respect to Au(111). Both the Cd and S monolayers appear to be nearly closest-packed, in contrast to the more open structures observed in the S-first films. Interestingly, the second monolayers of Cd and S were found to have the same structure as in the first monolayer of CdS, implying that the first two CdS monolayers are epitaxial. Only after deposition of the third monolayer of CdS are interatomic spacings characteristic of bulk CdS observed. Micrometer-resolution STM images reveal a significant decrease in pit density, average pit diameter, and average pit depth for the Cd-first films compared to that for the S-first films. Finally, resonance Raman data indicate that S-first films are significantly more polydisperse than Cd-first films. Taken together, these data point to a structural rearrangement in the first monolayer of CdS as the origin of the increased polycrystallinity in the S-first films. In contrast, the closest-packed structures formed when Cd is deposited first lead to films with fewer defects. The implications of these findings on the electrosynthesis of thin film materials is briefly discussed.

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“…In addition, SEM revealed the presence of a low density of small, surface particles before and after annealing. The composition of these particles was not determined independently of the bulk, although other researchers have found similar particles to be either Hg-rich (8,13) or identical to the bulk (10).…”

Section: Resultsmentioning

confidence: 99%

Thin‐Film Cadmium Mercury Telluride Prepared by Nonaqueous Electrodeposition

Colyer

Cocivera

1992

J. Electrochem. Soc.

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Using a new electrodeposition process, thin-film cadmium mercury telluride, Cd=Hg~_=Te, with (1 -x) no greater than 0.4, was electrodeposited onto an indium tin oxide-coated glass cathode. The deposition bath contained Cd(II), Hg(II), and tri-n-butyl phosphine telluride in propylene carbonate, and its composition was shown to have a direct effect on the composition of the electrodeposited films. Film composition was determined by atomic absorption spectroscopy and by proton-induced x-ray emission. Structural analysis of the cadmium mercury telluride films was achieved by way of scanning electron microscopy and x-ray diffractometry. Crystallinity of the films was shown to increase following heat-treatment in either argon or air. The bandgaps, which were determined by measuring the optical absorption spectra of these materials, were shown to decrease with increasing (1 -x), as predicted by an empirical expression.

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Growth of CdxHg1−xTe semiconductor films by electrodeposition technique

Cited by 8 publications

References 8 publications

A Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy Study of Electrochemically Grown ZnS Monolayers on Au(111)

A Scanning Tunneling Microscopy and X-ray Photoelectron Spectroscopy Study of Electrochemically Grown ZnS Monolayers on Au(111)

Electrochemistry of S Adlayers at Underpotentially Deposited Cd on Au(111): Implications for the Electrosynthesis of High-Quality CdS Thin Films

Thin‐Film Cadmium Mercury Telluride Prepared by Nonaqueous Electrodeposition

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