The material used for 380nm to 530nm wavelength products is indium gallium nitride (InGaN). It is technically possible to make a wavelength anywhere between 395nm and 530nm. However, most large suppliers concentrate on creating blue (450nm - 475nm) LEDs for making white light with phosphors, and green LEDs that fall into the 520nm - 530nm range for traffic signal green lighting. Rapid advancements and improvements in efficiency are noted in the blue wavelength  range, especially, as the race to create brighter and brighter, white illumination sources continues.