Spontaneous Seed Formation During Electrodeposition Drives Epitaxial Growth of Metastable Bismuth Selenide Microcrystals

20 May 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Materials with metastable phases can exhibit vastly different properties from their thermodynamically favored counterparts. Methods to synthesize metastable phases without the need for high-temperature or high-pressure conditions would facilitate their widespread use. We report on the electrochemical growth of microcrystals of bismuth selenide, Bi2Se3, in the metastable orthorhombic phase at room temperature in aqueous solution. Rather than direct epitaxy with the growth substrate, the spontaneous formation of a seed layer containing nanocrystals of cubic BiSe enforces the metastable phase. We first used single-crystal silicon substrates with a range of resistivities and different orientations to identify the conditions needed to produce the metastable phase. When the applied potential during electrochemical growth is positive of the reduction potential of Bi3+, an initial, Bi-rich seed layer forms. Electron microscopy imaging and diffraction reveal that the seed layer consists of nanocrystals of cubic BiSe embedded within an amorphous matrix of Bi and Se. Using density-functional theory calculations, we show that epitaxial matching between cubic BiSe and orthorhombic Bi2Se3 can help stabilize the metastable orthorhombic phase over the thermodynamically stable rhombohedral phase. The spontaneous formation of the seed layer enables us to grow orthorhombic Bi2Se3 on a variety of substrates including single-crystal silicon with different orientations, polycrystalline fluorine-doped tin oxide, and polycrystalline gold. The ability to stabilize the metastable phase through room-temperature electrodeposition in aqueous solution without requiring a single-crystal substrate, broadens the range of applications for this semiconductor in optoelectronic and electrochemical devices.


bismuth selenide
seeded growth

Supplementary materials

Supporting Information for Spontaneous Seed Formation During Electrodeposition Drives Epitaxial Growth of Metastable Bismuth Selenide Microcrystals
Supporting discussion of the search process for Bi–Se compounds in the ISCD and the formation enthalpy of Bi2Se3 when interfaced with the (110) surface of cubic BiSe; Supporting tables providing details of the silicon substrates, the electrodeposition parameters used to grow Bi2Se3 films, a summary of the structures of Bi–Se compounds, and calculated surface energies of BiSe and Bi2Se3; Supporting figures showing current traces during electrodeposition of Bi2Se3, powder XRD patterns of Bi2Se3 films, cyclic voltammograms in a solution of SeO2, additional characterization of the seed layer, SEM images of rhombohedral Bi2Se3 films, additional XPS results, the unit cell of cubic BiSe, simulated diffraction pattern of Bi2Se3 with the Zn3P2 structure, additional cross-sectional TEM images and electron diffraction patterns, coincident site lattice models, change in the formation enthalpy of Bi2Se3 matched with the cubic BiSe (110) surface, cyclic voltammograms in a solution of Bi(NO3)3 using Au and FTO substrates.


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