Title :
High brightness InGaN green LEDs with an ITO on n++-SPS upper contact
Author :
Chang, C.S. ; Chang, S.J. ; Su, Y.K. ; Kuo, C.H. ; Lai, W.C. ; Lin, Y.C. ; Hsu, Y.P. ; Shei, S.C. ; Tsai, J.M. ; Lo, H.M. ; Ke, J.C. ; Sheu, J.K.
Author_Institution :
Dept. of Electr. Eng., Nat. Cheng Kung Univ., Taiwan, Taiwan
Abstract :
Indium tin oxide (ITO) (260 nm) and Ni (5 nm)/Au (10 nm) films were deposited onto glass substrates, p-GaN layers, n+-InGaN/GaN short-period-superlattice (SPS), n++-SPS and nitride-based green light-emitting diodes (LEDs). It was found that ITO could provide us an extremely high transparency (i.e., 95% at 520 nm). It was also found that the 1.03×10-3 Ωcm2 specific contact resistance of ITO on n++-SPS was reasonably small. Although the forward voltage of the LED with ITO on n++-SPS upper contacts was slightly higher than that of the LED with Ni/Au on n++-SPS upper contacts, the 20 mA output power and external quantum efficiency of the former could reach 4.98 mW and 8.2%, respectively, which were much larger than the values observed from the latter. The reliability of ITO on n++-SPS upper contacts was also found to be reasonably good.
Keywords :
III-V semiconductors; contact resistance; gallium compounds; indium compounds; light emitting diodes; ohmic contacts; semiconductor device reliability; semiconductor superlattices; tin compounds; transparency; wide band gap semiconductors; 10 nm; 20 mA; 260 nm; 4.98 mW; 5 nm; 520 nm; 8.2 percent; ITO; ITO on n++-SPS upper contact; InGaN-GaN; InSnO; Ni-Au; Ni/Au films; external quantum efficiency; extremely high transparency; forward voltage; glass substrates; high brightness InGaN green LEDs; n+-InGaN/GaN short-period-superlattice; output power; p-GaN layers; reliability; specific contact resistance; Brightness; Contact resistance; Gallium nitride; Gold; Indium tin oxide; Ionization; Light emitting diodes; Superlattices; Tunneling; Voltage;
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2003.819091
