Disclosed are methods of improving performance characteristics and functionalities of photonic and electronic devices consisting of semiconductor materials with polarization properties in order to address technical challenges in next generation solid-state lighting, electronics, electro-mechanics, and photonics. In this invention disclosure, we describe that electronic band structures of polar semiconductors having a layer consisting of anions or cations on a surface such as GaN-based (Al.Gayln1 .• ,yN)- and ZnO-based (MgxZnyCdi+yO) materials can be engineered for multifunctional and/or high-performance devices by external strains. In particular, we claim that (1) optical output power and efficiency of visible light-emitting diodes (LEDs) are improved by optimum bending of semiconductor structures; (2) emission wavelength of LED are changed by external strain which is related to wavelength-tunable LEDs; (3) red, green, blue (R/G/B) LEDs are realized from the same materials by corrugated and other-form semiconductor structures for phosphor-free white LEDs; (4) conductivity in a channel of transistors is modulated by bending of semiconductor structures; (5) this concept leads to a new device named strain-effect transistors (SETs). The new concept and process are expected to provide a solution that can overcome the technological limitations in current energy-saving devices and systems.