Low temperature studies of the efficiency droop in InGaN-based light-emitting diodes
- Title
- Low temperature studies of the efficiency droop in InGaN-based light-emitting diodes
- Author
- 심종인
- Keywords
- efficiency droop; electroluminescence; internal quantum efficiency; low temperature; nonradiative recombination; open-circuit voltage; photoluminescence; saturation of radiative recombination rate
- Issue Date
- 2014-00
- Publisher
- SPIE
- Citation
- Proceedings of SPIE - The International Society for Optical Engineering, v. 8986, article no. 89861S, Page. 1-8
- Abstract
- The efficiency droop in light-emitting diodes (LEDs) represents a gradual decrease of the internal quantum efficiency (IQE) with increasing current. Experimentally, the IQE droops are strong functions of material, epitaxial and chip structures, and operating temperature. Recently, we have proposed an IQE droop model as the saturation of the radiative recombination rate at low current and subsequent increase in the nonradiative recombination rates at high current. Once the radiative recombination rate begins to saturate at an active region, the carrier density as well as the nonradiative recombination rate rapidly increase there. Eventually, the IQE droop appears from the increase in the nonradiative recombination rate being much larger than that in the radiative one. A dominant nonradiative recombination process is not solely determined for each LED chip, but it could vary with current level and operating temperature. As temperature decreases, in general, the IQE droop becomes larger with the peak IQE occurring at an extremely small current level. We test the droop model by investigating the radiative and nonradiative recombination processes separately from the cryogenic to room temperature. The characterization methods include comparative efficiency study between photoluminescence (PL) and electroluminescence (EL), open-circuit voltage under resonant PL excitation, interrelations of current-voltage-light characteristics, and EL spectra of color-coded quantum wells (QWs). Although a sudden increase of the nonradiative recombination rate is an apparent cause of the IQE droop, the saturation of the radiative recombination rate is the common trigger behind the IQE droop issue. © 2014 SPIE.
- URI
- https://www.spiedigitallibrary.org/conference-proceedings-of-spie/8986/1/Low-temperature-studies-of-the-efficiency-droop-in-InGaN-based/10.1117/12.2037986.short?SSO=1https://repository.hanyang.ac.kr/handle/20.500.11754/184033
- ISSN
- 0277-786X
- DOI
- 10.1117/12.2037986
- Appears in Collections:
- COLLEGE OF SCIENCE AND CONVERGENCE TECHNOLOGY[E](과학기술융합대학) > PHOTONICS AND NANOELECTRONICS(나노광전자학과) > Articles
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