Phosphor-Free InGaN/GaN Dot-in-a-Wire White Light-Emitting Diodes on Copper Substrates

We have developed a novel substrate-transfer procedure for phosphor-free nanowire (NW) white light-emitting diodes (LEDs), wherein the NWs are grown directly on an SiO2 etch-stop layer. By applying this technique, InGaN/GaN NW LEDs were successfully transferred from SiO2/Si(100) substrates to copper substrates to reduce substrate absorption and improve heat dissipation. Compared with NW LEDs on Si, NW LEDs on copper substrates have several advantages, including enhanced output power and better current-voltage characteristics. We also show that white light emission by NW LEDs on copper substrates is highly stable.