A semiconductor device is provided in which energy band gap can be electrically varied. The device includes nanowires embedded in a material that exhibits a deformation when properly addressed, e.g., a piezoelectric material such as lead zirconate titanate (PZT), aluminum nitride (A1N) or zinc oxide (Zn0). The nanowires can be reversibly strained by applying a local deformation to the piezoelectric material by applying a voltage to the material. The resulting band gap variation can be utilized to tune the color of the light emitted from e.g., a LED or a laser. Further, contact resistance in semiconductor junctions can be controlled, e.g., for use in memories and switches.