Exciton spectra in thin crystals: the diamagnetic effect

Abstract

The optical absorption spectrum of MoS2 shows two series of exciton absorption bands associated with direct optical transitions from a split valence band. The diamagnetic shifts of the exciton absorption bands (H[parallel]c, H[perpendicular]c) have been measured and values obtained for the exciton effective mass and anisotropy parameter (ellipsoidal model). In thin crystals the exciton absorption bands occur to the high-energy side of their positions in thick crystals and there is an associated diminution in the diamagnetic shifts.