TiO2 Band Gap Energy: Direct vs. Indirect

[Doeroo]

When we say generally TiO2 band gap energy, is it meaning direct or indirect band energy?
Some papers show only direct BG or indirect BG or both. Is it right that one semiconductor has one of direct and indirect BG. I am a little bit confused.

 

[MATLABdude]

The following came up in a Google search for 'titanium dioxide band structure' (which also has some references listed):
http://www.tyndall.ie/research/electronic-theory-group/cm4105/bandstructs/TiO2_b.pdf

It's been a while since my semiconductor theory class, but the discrepancy could come from the different crystalline structures and/or different transitions. There will also be a difference between bulk and thin-film (especially structured ones) properties.

EDIT: And welcome to PhysicsForums!