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Titolo:
Electrochemical formation of a III-V compound semiconductor superlattice: InAs/InSb
Autore:
Wade, TL; Vaidyanathan, R; Happek, U; Stickney, JL;
Indirizzi:
Univ Georgia, Dept Chem, Athens, GA 30602 USA Univ Georgia Athens GA USA 30602 Georgia, Dept Chem, Athens, GA 30602 USA Univ Georgia, Dept Phys & Astron, Athens, GA 30602 USA Univ Georgia Athens GA USA 30602 Dept Phys & Astron, Athens, GA 30602 USA
Titolo Testata:
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
fascicolo: 1-2, volume: 500, anno: 2001,
pagine: 322 - 332
Fonte:
ISI
Lingua:
ENG
Soggetto:
ATOMIC-LAYER EPITAXY; SCANNING-TUNNELING-MICROSCOPY; CADMIUM-SULFIDE MONOLAYERS; GALLIUM-ARSENIDE FILM; CUINSE2 THIN-FILMS; LOW-INDEX PLANES; PHOTOELECTROCHEMICAL PROPERTIES; ALTERNATED ELECTRODEPOSITION; AQUEOUS-ELECTROLYTES; GAAS DEPOSITION;
Keywords:
electrodeposition; compound semiconductor; III-V; bandgap; IR absorption; superlattice; EC-ALE; upd;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
90
Recensione:
Indirizzi per estratti:
Indirizzo: Stickney, JL Univ Georgia, Dept Chem, Athens, GA 30602 USA Univ Georgia Athens GA USA 30602 Chem, Athens, GA 30602 USA
Citazione:
T.L. Wade et al., "Electrochemical formation of a III-V compound semiconductor superlattice: InAs/InSb", J ELEC CHEM, 500(1-2), 2001, pp. 322-332

Abstract

We report on the use of electrochemical atomic-layer epitaxy (EC-ALE) to grow thin-films of the III-V compounds InAs, InSb, and an InAsxSb1-x, superlattice. EC-ALE is a method for forming compound semiconductors with improved control, compared to other electrodeposition methodologies. It involves the use of surface limited reactions to form deposits an atomic layer at a time, in a cycle. The EC-ALE cycle uses underpotential deposition (upd) to form atomic layers of each of the component elements. One cycle ideally produces one monolayer (ML) of the desired compound. Studies to optimize the InAs cycle are reported, specifically the dependence on the In and As deposition potentials. These studies show that the potentials must be adjusted foreach of the first 25 or more cycles, as a contact potential between the Ausubstrate and the growing semiconductor develops. After deposition of thisinitial 'buffer layer', steady state conditions are reached, and the same potentials can be used without change, for the remaining cycles. The formation of InSb has also been investigated, and the EC-ALE growth of InSb deposits is reported for the first time. Due to a 6% lattice mismatch, and a less than fully optimized cycle, the InSb deposits on Au appear composed of 70nm particles. By combining the InAs and InSb programs, a superlattice was formed with 41 periods, where each period involved ten cycles of InAs followed by ten cycles of InSb. X-ray diffraction (XRD) indicated a period of 5.5 nm, whereas a 7.4 nm period was expected, based on 1 ML/cycle and the (111) interplanar spacing, derived from the lattice constants for InAs and InSb. Given the stoichiometry of the resulting deposit, and the shorter periodicity observed, it appears that 1 ML/cycle of InAs was formed, while only a1/2 ML/cycle of InSb was obtained. IR absorption measurements indicate that the deposit was red shifted relative to the lower bandgap compound, InSb (0.17 eV), which is consistent with a type II superlattice. If an alloy hadbeen formed, the bandgap should have been a linear function of the bandgaps and relative mole fractions of InAs and InSb, or about 0.31 eV, twice theobserved bandgap. (C) 2001 Elsevier Science B.V. All rights reserved.

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Documento generato il 08/04/20 alle ore 08:57:10