한국진공학회:학술대회논문집 (Proceedings of the Korean Vacuum Society Conference)
- 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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- Pages.280.1-280.1
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- 2016
Effect of Si-doping on the luminescence properties of InGaN/GaN green LED with graded short-period superlattice
- Cho, Il-Wook (Kangwon National University) ;
- Lee, Dong Hyun (Kangwon National University) ;
- Ryu, Mee-Yi (Kangwon National University) ;
- Kim, Jin Soo (Chonbuk National University)
- 발행 : 2016.02.17
초록
Generally InGaN/GaN green light emitting diode (LED) exhibits the low quantum efficiency (QE) due to the large lattice mismatch between InGaN and GaN. The QE of InGaN-based multiple quantum wells (MQWs) is drastically decreased when an emission wavelength shifts from blue to green wavelength, so called "green gap". The "green gap" has been explained by quantum confined Stark effect (QCSE) caused by a large lattice mismatch. In order to improve the QE of green LED, undoped graded short-period InGaN/GaN superlattice (GSL) and Si-doped GSL (SiGSL) structures below the 5-period InGaN/GaN MQWs were grown on the patterned sapphire substrates. The luminescence properties of InGaN/GaN green LEDs have been investigated by using photoluminescence (PL) and time-resolved PL (TRPL) measurements. The PL intensity of SiGSL sample measured at 10 K shows stronger about 1.3 times compared to that of undoped GSL sample, and the PL peak wavelength at 10 K appears at 532 and 525 nm for SiGSL and undoped GSL, respectively. Furthermore, the PL decay of SiGSL measured at 10 K becomes faster than that of undoped GSL. The faster decay for SiGSL is attributed to the increased wavefunction overlap between electron and hole due to the screening of piezoelectric field by doped carriers. These PL and TRPL results indicate that the QE of InGaN/GaN green LED with GSL structure can be improved by Si-doping.