CuZnSnSe thin films were deposited by thermal vacuum evaporation with and without argon gas stream at room temperature. Effect of argon gas on surface morphology and on photoelectrochemical (PEC) characteristics of the films was studied. The electrodes prepared under argon gas showed better enhanced characteristics, due to slower nucleation and growth due to dilution effect of the inert gas. While both electrodes showed soundly good PEC behaviors in a hexacyanoferrate(III)/hexacyanoferrate(II) redox couple, the electrode with argon gas showed 20 fold enhancement in photoactivity, compared to the one without argon gas. The results manifested thin film electrode performance can be enhanced simply by inclusion of argon inert gas inside the preparation chamber, with no need for other procedures such as annealing.