Title :
Internal Quantum Efficiency Enhancement by Relieving Compressive Stress of GaN-Based LED
Author :
Yi Chin Lin ; Wei Chih Liu ; Chia Lun Chang ; Chao Chi Chung ; Yan Hao Chen ; Te Yuan Chung ; Cheng Yi Liu
Author_Institution :
Dept. of Chem. Eng. & Mater. Eng., Nat. Central Univ., Jhongli, Taiwan
Abstract :
By die-attaching GaN-based light-emitting diodes (LEDs) on Si substrates with eutectic AuSn solder, the external quantum efficiency of the LEDs was enhanced by 3.5% at a current input of 120 A/cm2. The enhancement of the external quantum efficiency of the die-attached LED chips is attributed to a reduction in compressive stress and piezoelectric fields in quantum wells after eutectic AuSn die-attachment. Raman and photoluminescence analyses were used to estimate the reduction in compressive stress and piezoelectric field in quantum wells, which is 277.8 MPa and 0.056 MV/cm, respectively, after AuSn die-attachment.
Keywords :
Raman spectra; eutectic alloys; gold alloys; light emitting diodes; microassembling; photoluminescence; piezoelectric devices; piezoelectric semiconductors; piezoelectricity; quantum well devices; semiconductor quantum wells; solders; tin alloys; GaN-AuSn; GaN-based LED; Raman spectra; Si; compressive stress; current input; die-attached LED chips; die-attaching GaN-based light-emitting diodes; eutectic die-attachment; eutectic solder; external quantum efficiency; internal quantum efficiency enhancement; photoluminescence; piezoelectric fields; quantum wells; Compressive stress; Energy states; Gallium nitride; Light emitting diodes; Silicon; Substrates; GaN light-emitting diode (LED); internal quantum efficiency; piezoelectric field; stress;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2014.2329857
