Title :
Reducing a Piezoelectric Field in InGaN Active Layers by Varying Pattern Sapphire Substrates
Author :
Chia-Feng Lin ; Kuei-Ting Chen ; Wang-Po Tseng ; Bing-Cheng Shieh ; Chang-Hua Hsieh
Author_Institution :
Dept. of Mater. Sci. & Eng., Nat. Chung Hsing Univ., Taichung, Taiwan
Abstract :
Internal quantum efficiency (IQE) and piezoelectric field (PZ) in InGaN light-emitting diodes (LEDs) were analyzed that were grown on a truncated pyramid (TP)- and a pyramid (P)-shaped pattern sapphire substrates. Lower flat-band voltage was measured at -8 V in the P-LED compared with the TP-LED (-12 V) that showed a low PZ was observed in the P-LED structure. The IQE value of the P-LED was measured as 86%, which is higher than that of the TP-LED (76%). High IQE, low PZ, and high light extraction efficiency were observed in the InGaN LED structure grown on the P-shaped pattern sapphire substrate.
Keywords :
light emitting diodes; piezoelectric materials; IQE; InGaN; LED structure; internal quantum efficiency; light emitting diodes; piezoelectric field; truncated pyramid; varying pattern sapphire substrates; voltage -12 V; voltage -8 V; Gallium nitride; Laser excitation; Light emitting diodes; Power lasers; Substrates; Voltage measurement; Wavelength measurement; InGaN; pattern sapphire; piezoelectric field (PZ);
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2013.2284918
