Aluminium gallium antimonide

The bandgap and lattice constant of AlGaSb alloys are between those of pure AlSb (a = 0.614 nm, Eg = 1.62 eV) and GaSb (a = 0.610 nm, Eg = 0.73 eV).

[3] At an intermediate composition, the bandgap transitions from an indirect gap, like that of pure AlSb, to a direct gap, like that of pure GaSb.

[3][4][5] The spread in the reported values of the transition is mainly due to the closeness of the gap sizes at the Γ and L points in the Brillouin zone and variations in the experimentally-determined gap sizes.

[3] AlGaSb has been incorporated into devices such as heterojunction bipolar and high-electron-mobility transistors,[6][7][8] resonant-tunneling diodes,[9] solar cells,[10] short-wave infrared lasers,[11] and a novel infrared light modulator.

[12] It is sometimes selected as an interlayer or buffer layer in studies of GaSb and InAs quantum wells.

Dependence of the direct and indirect band gaps of AlGaSb on composition at room temperature (T = 300 K). [ 3 ] Based on these recommended empirical relationships, the transition from a direct (Γ–Γ) to indirect (Γ–X) gap occurs at x = 0.43.