An InGaN-GaN blue light-emitting diode (LED) structure and an InGaN-GaN green LED structure were grown sequentially onto the same sapphire substrate so as to achieve a nitride-based near white LED. In order to avoid thyristor effect, we choose a large 2.1 × 2.1 mm2 LED chip size, which was six times larger than that of the normal LED. It was found that we could observe a near white light emission with commission international de l'Eclairage color coordinates x = 0.2 and y = 0.3, when the injection current was lower than 200 mA. It was also found that the output power, luminous efficiency and color temperature of such a cascade near white LED were 4.2 mW, 81 lm/W, and 9000 K, respectively.
- White LED