Stable temperature characteristics of InGaN blue light emitting diodes using AlGaN/GaN/InGaN superlattices as electron blocking layer

P-type AlGaN/GaN/InGaN superlattices were incorporated in a InGaN based blue light emitting diode as electron blocking layer to minimize the temperature dependence on optical output power. For the characteristic temperatures in range of 10 to 100 °C and at operation current of 350 mA, the external quantum efficiency varied by less than 0.5%. For the presented device, the negative characteristic temperature was shown to occur below temperature of 50 °C. The improved temperature stability in optical output power is thought to be attributed to (1) the efficiency of hole carrier transport in AlGaN/GaN/InGaN superlattices and (2) the enhanced blocking of electron overflow between multiple quantum wells and AlGaN/GaN/InGaN superlattices.