A photovoltaic device including a rear electrode which may also function as a rear reflector. In certain example embodiments, the rear electrode comprises a reflective film (e.g., of Mo or the like) including one or more layers provided on an interior surface of a rear glass substrate of the photovoltaic device. In certain example embodiments, the interior surface(s) of the rear glass substrate and/or reflective film is/are textured so as to provide desirable electrical and reflective characteristics. The rear glass substrate and textured rear electrode/reflector are used in a photovoltaic device (e.g., CIS or CIGS solar cell) where an active semiconductor film is provided between the rear electrode/reflector and a front electrode(s).