[4] While stoichiometric bismuth selenide should be a semiconductor with a gap of 0.3 eV, naturally occurring selenium vacancies act as electron donors, so Bi2Se3 is intrinsically n-type.

[12][13][14][15] Bismuth selenide is a van der Waals material consisting of covalently bound five-atom layers (quintuple layers) which are held together by van der Waals interactions[16] and spin-orbit coupling effects.

For this reason, the Bi2Se3 surface is an interesting candidate for van der Waals epitaxy and subject of scientific research.

For instance, different phases of antimony layers can be grown on Bi2Se3,[18][19] by means of which topological pn-junctions can be realised.

[21][22] Although bismuth selenide occurs naturally (as the mineral guanajuatite) at the Santa Catarina Mine in Guanajuato, Mexico[23] as well as some sites in the United States and Europe,[24] such deposits are rare and contain a significant level of sulfur[24] atoms as an impurity.