Epitaxial Electrodeposition of Wide Bandgap Cuprous Bromide on Silver Via a Silver Bromide Buffer Layer
Cuprous halides are an important class of wide bandgap p-type semiconductors used in opto-electronics. Cuprous bromide (CuBr) shows potential for short-wavelength devices due to a large exciton binding energy (108 meV) and near-ultraviolet bandgap (3.1 eV). However, the growth of high-quality epitaxial CuBr films by electrodeposition has remained a challenge. Here, we introduce a low-cost electrochemical procedure for producing epitaxial CuBr(111) on a Ag(111) substrate by a -oriented silver bromide (AgBr) buffer layer. The AgBr buffer layer forms during the electrodeposition of the CuBr. The mismatch between CuBr(111) and AgBr(111) is −1.3%. A plausible mechanism for nucleation and growth of the epitaxial CuBr is proposed. X-ray techniques including high resolution X-ray diffraction and X-ray pole figures are used to determine the epitaxial relationship. CuBr(100) is also produced on a Ag(100) surface by a AgBr(100) buffer layer that is rotated in-plane 45° relative to the Ag(100) surface. This in-plane rotation reduces the lattice mismatch from +39.5% for an unrotated film to −1.4% for a 45° rotated film.
B. Luo et al., "Epitaxial Electrodeposition of Wide Bandgap Cuprous Bromide on Silver Via a Silver Bromide Buffer Layer," Journal of the Electrochemical Society, vol. 169, no. 9, article no. 092512, The Electrochemical Society, Sep 2022.
The definitive version is available at https://doi.org/10.1149/1945-7111/ac8eeb
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01 Sep 2022