How does doping affect the color of a semiconductor?

Dopant affects band gap of material. The band gap determines the wavelength of light that the material absorbs. The color of material depends on what light it absorbs. Maybe P/N dope affects color of material. If you draw the band gap of material using any method (Density functional Theory or etc), you can predict color of material some extent. In real world, color of material is more complex than I said. I don't know if it can predict the color of matter perfectly.