  It has been well established that single layer MX2 (M=Mo,W and X=S,Se) are
direct gap semiconductors with band edges coinciding at the K point in contrast
to their indirect gap multilayer counterparts. In few-layer MX2, there are two
valleys along the {\Gamma}-K line with similar energy. There is little
understanding on which of the two valleys forms the conduction band minimum
(CBM) in this thickness regime. We investigate the conduction band valley
structure in few-layer MX2 by examining the temperature-dependent shift of
indirect exciton PL. Hihgly anisotropic thermal expansion of the lattice and
corresponding evolution of the band structure result in distinct peak shift for
indirect transitions involving the K and {\Lambda} (midpoint along {\Gamma}-K)
valleys. We identify the origin of the indirect emission and concurrently
determine the relative energy of these valleys. Our results show that the two
valleys compete in energy in few-layer WSe2.
