While energy production and distribution have always been a challenge, today it is increasingly urgent to reduce power consumption — and lighting is no exception. Light-emitting diodes or LEDs provide an alternative to conventional lighting for consuming less power, lower thermal dissipation, and longer life. In fact, LED products are already spurring evolution in lighting, and it is anticipated that power LEDs will lead the way in combining high intensity and efficiency. So what is the structure of LEDs, and how do they emit light?