Synthesis and Characterization of Monocrystalline GaPSi3 and (GaP)y(Si)5-2y Phases with Diamond-like Structures via Epitaxy-Driven Reactions of Molecular Hydrides

Patrick E. Sims, Chi Xu, Christian D. Poweleit, Jose Menendez, John Kouvetakis

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Hybrid (III-V)-(IV) alloys described using the general formula (GaP)y(Si)5-2y have been synthesized as epitaxial layers on Si(100) using specially designed chemical vapor deposition methods. Reactions of [D2GaN(CH3)2]2 with P(SiH3)3 between 525 and 540 °C gave GaPSi3 (y = 1) with a fixed Si content of 60%, while analogous reactions of [H2GaN(CH3)2]2 at >590 °C produced Si-rich derivatives with tunable Si contents in the range of 75-95% (y < 1). In both cases, diffraction studies and optical characterizations demonstrate single-phase, monocrystalline structures with an average diamond cubic lattice akin to Si. Raman scattering supports the presence of a tetrahedral structure containing isolated Ga-P pairs randomly embedded within the parent Si matrix. This outcome is consistent with theoretical simulations of a crystal growth mechanism involving interlinking GaPSi3 tetrahedra in a manner that precludes the formation of energetically unfavorable Ga-Ga bonds. Ellipsometry measurements of the dielectric function reveal systematic tuning of the absorption coefficient as a function of composition and demonstrate an enhanced optical response in the visible range relative to crystalline Si. The seamless integration with Si wafers and the intriguing optical response suggest these materials are promising candidates for optoelectronic applications.

Original languageEnglish (US)
Pages (from-to)3202-3210
Number of pages9
JournalChemistry of Materials
Volume29
Issue number7
DOIs
StatePublished - Apr 11 2017

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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