Enhanced optical properties of InGaN MQWs with InGaN underlying layers

Son, J. K.; Sn, Lee; Sakong, T.; Paek, H. S.; Nam, Ok Hyun; Park, Y; Hwang, Jinyoung; Jy, Kim; Cho, Yong-Hoon

doi:10.1016/j.jcrysgro.2005.10.071

Cited by 29 publications

(17 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, in room temperature, luminescence efficiency is governed by non-radiative recombination process related to point defects in a QW [3,4]. By compared between samples with different QW thicknesses, the radiative lifetimes are decreasing as QW thickness increasing, which is explained by the reduction of electronhole wavefunction overlap in the tilted potential induced by piezo-electric field rather than the increase of non-radiative recombination centers in the highly localized potential.…”

mentioning

confidence: 96%

Radiative and non‐radiative transitions in blue quantum wells embedded in AlInGaN‐based laser diodes

Son

Lee

Paek

et al. 2007

Phys. Status Solidi (c)

Self Cite

View full text Add to dashboard Cite

We performed temperature-dependent time-resolved optical studies (TRPL) on AlInGaN-based bluelight-emitting quantum well (QW) with different well widths. Radiative and non-radiative components of PL lifetime were analyzed by measuring intensity and lifetime of PL. We experimentally confirmed that a non-radiative lifetime was affected by internal field in InGaN QWs. Therefore, non-radiative lifetimes were reduced as a well width decreasing in the same way that radiative lifetimes do. In addition, the more efficient optical properties of QWs, such as internal quantum efficiency, were achieved in the narrow QWs rather than the wider one. 1 Introduction A progress in InGaN-based semiconductors technology has successfully achieved the manufacture of highly efficient laser diodes (LDs) [1]. In addition to operational wavelength of LDs from violet to blue spectral regions, bluish green (480 nm) and true-green (530 nm) emissions are demanded for bio-medical and display applications. However, a stable operation of LDs in relatively long wavelength region (> 470 nm) is suffering from a high threshold current and low slope efficiency, as well as an enormous blue-shift of emission wavelength under increasing input current [2]. In particular, an efficiency of InGaN quantum wells (QWs) is drastically reduced as emission wavelength increases in range from 450 nm to 520 nm. As a result, active medium can not provide enough gain to obtain threshold condition of LD.In InGaN-based band gap materials, a non-radiative recombination of carriers is an important process, which governs luminescence mechanism at room temperature [3]. In this report, we studied systematically a non-radiative life time in blue-green QWs so as to figure out the correlation between QW's efficiency in LDs and non-radiative process under the In-rich environment, which have the Quantum Confined Stark Effect (QCSE) induced by piezo-electric field and the highly localized potential due to In fluctuation in QWs.It is observed that PL lifetime is determined by radiative process in low T regime (< 100 K) but, in room temperature, non-radiative transition is almost 10 times faster than radiative one. Therefore, in room temperature, luminescence efficiency is governed by non-radiative recombination process related to point defects in a QW [3,4]. By compared between samples with different QW thicknesses, the radiative lifetimes are decreasing as QW thickness increasing, which is explained by the reduction of electronhole wavefunction overlap in the tilted potential induced by piezo-electric field rather than the increase of non-radiative recombination centers in the highly localized potential. In addition, we observe that nonradiative lifetimes are also decreasing with increasing well width in such a way that the variation of nonradiative lifetimes is influenced by piezo-electric effect as well. The change of non-radiative lifetime is

show abstract

mentioning

confidence: 96%

Radiative and non‐radiative transitions in blue quantum wells embedded in AlInGaN‐based laser diodes

Son

Lee

Paek

et al. 2007

Phys. Status Solidi (c)

Self Cite

View full text Add to dashboard Cite

show abstract

“…Inclusion of an In 0.02-Ga 0.98 N UL is representative of InGaN ULs employed in InGaN/GaN MQWs for improved IQE. 11 Two InGaN heterostructures were grown on pGaN:Mg templates under conditions nominally identical to MQWs. The first DLOS heterostructure (sample A) consisted of a 12.5-nm-thick In 0.17-Ga 0.83 N cap layer, which represents the optically active well layer of a MQW structure, grown on top of a $200-nm-thick UID In 0.02 Ga 0.98 N UL.…”

Section: Methodsmentioning

confidence: 99%

Quantitative and Depth-Resolved Investigation of Deep-Level Defects in InGaN/GaN Heterostructures

Armstrong

Crawford

Koleske

2010

Journal of Elec Materi

View full text Add to dashboard Cite

0.17 Ga 0.83 N/In 0.02 Ga 0.98 N/p-GaN:Mg heterostructures were studied using deep-level optical spectroscopy (DLOS). Depth-resolved DLOS was achieved by exploiting the polarization-induced electric fields to discriminate among defects located in the In 0.17 Ga 0.83 N and the In 0.02 Ga 0.98 N regions. Growth conditions for the In x Ga 1Àx N layers were nominally the same as those in InGaN/GaN multi-quantum-well (MQW) structures, so the defect states reported here are expected to be active in MQW regions. Thus, this work provides important insight into defects that are likely to influence MQW radiative efficiency. In 0.17 Ga 0.83 N-related bandgap states were observed at E v + 1.60 eV and E v + 2.59 eV, where E v is the valence-band maximum, compared with levels at E v + 1.85 eV, E v + 2.51 eV, and E v + 3.30 eV in the In 0.02 Ga 0.98 N region. A lighted capacitance-voltage technique was used to determine the areal density of deep states. The possible origins of the associated defects are considered along with their potential roles in light-emitting diodes.

show abstract

“…The factors impacting IQE of MQW include the crystal quality of the MQW, the spatial distribution of the In content [1], and the quantum confine Stark effect (QCSE) [2]. There have been some articles reporting the increase of the IQE of MQW by using an InGaN underneath layer (UL) [3][4][5]. They mainly attributed the increase of the IQE to the decrease of the nonradiative centers (NRCs) due to a more uniform In distribution in MQW.…”

Section: Introductionmentioning

confidence: 99%

Study on internal quantum efficiency of blue InGaN multiple-quantum-well with an InGaN underneath layer

Wang

Zhao

et al. 2010

Sci. China Technol. Sci.

View full text Add to dashboard Cite

Blue InGaN multiple-quantum-well (MQW) samples with different In x Ga 1-x N (x=0.01-0.04) underneath layers (ULs) were grown by metal organic vapor phase epitaxy (MOVPE). Temperature dependent photoluminescence showed that the InGaN UL can improve the internal quantum efficiency (IQE) of MQW effectively due to strain release. And a maximum IQE of 50% was obtained when the thickness and In content of the InGaN UL were 60 nm and 0.01, respectively. Furthermore, the larger In content or thickness of the InGaN UL makes the IQE lower. Arrhenius fit to the experiment data showed that the IQE fall was mainly caused by the quantity increase of the nonradiative recombination centers, which was believed related to the accumulated stress in InGaN ULs. InGaN underneath layer (UL), multiple-quantum-well (MQW), internal quantum efficiency (IQE), Arrhenius formula Citation:Wang J X, Wang L, Zhao W, et al. Study on internal quantum efficiency of blue InGaN multiple-quantum-well with an InGaN underneath layer. Sci

show abstract

Enhanced optical properties of InGaN MQWs with InGaN underlying layers

Cited by 29 publications

References 7 publications

Radiative and non‐radiative transitions in blue quantum wells embedded in AlInGaN‐based laser diodes

Radiative and non‐radiative transitions in blue quantum wells embedded in AlInGaN‐based laser diodes

Quantitative and Depth-Resolved Investigation of Deep-Level Defects in InGaN/GaN Heterostructures

Study on internal quantum efficiency of blue InGaN multiple-quantum-well with an InGaN underneath layer

Contact Info

Product

Resources

About