GeSe (Germanium Selenide)

A layered van der Waals group-IV monochalcogenide with an orthorhombic, puckered structure analogous to black phosphorus, space group Pnma. It is a narrow-bandgap semiconductor with strong in-plane anisotropy in its electrical, optical, and thermoelectric properties. The non-centrosymmetric puckered lattice hosts in-plane ferroelectricity and pronounced piezoelectric and nonlinear optical responses, making GeSe an important earth-abundant, non-toxic candidate for anisotropic optoelectronics, photovoltaics, and two-dimensional ferroelectrics.

Growth method: Chemical vapor transport (CVT).

Sample specifications: Individual crystals measure approximately 5 mm, with a purity of up to 99.9999% (6N), and multiple high-quality single-crystal pieces included in each package.

Exfoliation: Difficult — strong interlayer bonding; mechanical exfoliation typically yields thick flakes, and ultrathin flakes are challenging to isolate.