Institute of Electrical and Electronics Engineers Inc.;IEEE
摘要:
摘要： Distinct temperature-dependent dynamic behaviors of GaN-based blue light-emitting diodes (LEDs) are observed by use of the very-fast electrical-optical pump-probe technique. Our static and impulse response measurement results indicate that the behaviors of internal carrier dynamics under different ambient temperatures can be classified into three regimes covering a wide range of bias current densities (20-2000 A/cm 2 ). The first regime is when the bias current density ranges from low to moderate (20-100 A/cm 2 ). The measured external quantum efficiency (EQE) degrades dramatically from 57 to 44%, and the measured waveform and extracted time constants of measured impulse responses are invariable from room temperature (RT) to 200 °C, which indicates that the carrier leakage is not an issue for the observed droop phenomenon. When the bias current density further increases to near 1 kA/cm 2 , the droop phenomenon are mitigated (44 to 24%). However, a significant shortening of the measured impulse response happens under 200 °C operation due to the device-heating effect. This phenomenon is diminished when the bias current densities are further increased to over 1 kA/cm 2 , due to the screening of the piezoelectric field. The extracted time constants can also be used to explain the droop phenomenon in GaN LED under high bias currents. 其他題名： JPHOT 出版者： IEEE 出版日期： 2012-10-01 出處： IEEE photonics journal, 2012-10, Vol.4 (5), p.1870-1880 資源來源： IEEE Xplore 識別號： ISSN: 1943-0655 識別號： ISSN: 1943-0647 識別號： EISSN: 1943-0647 識別號： DOI: 10.1109/JPHOT.2012.2217947 識別號： CODEN: PJHOC3
