We report on the characteristics of metal-p-type high resistance TlGaSe2 semiconductor junction barrier fabricated by deposition of indium and gold metals. The electrical properties of /TlGaSe2/ semiconductor contacts were monitored as a function of temperature in the range of similar to 80-300 K using current-voltage (I - V) and capacitance-voltage (C - V) measurements. Device characteristics of In/TlGaSe2/Au showed rectification properties. From forward bias I - V characteristics it was revealed that the increase of current is slower than the predictions by Schottky barrier theory. The rectification properties of In/TlGaSe2/Au semiconductor device were simulated by the Mott barrier model where the presence of an undoped layer on the semiconductor surface is assumed, and measurements and computational simulation agreed on the validity of this model.