The effect of InGaN underlayers on the electronic and optical properties of InGaN/GaN quantum wells

Li, T.; Wei, Qize; Fischer, Alec M.; Huang, Jeng-Jie; Huang, Y. U.; Ponce, Fernando; Liu, J. P.; Lochner, Zachary; Ryou, Jae Hyun; Dupuis, R. D.

doi:10.1063/1.4789758

Cited by 20 publications

(21 citation statements)

References 14 publications

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“…This is in line with a previous analyses of the effects of prelayers 13,14,26 where the shift in the emission energies and the changes in the radiative decay rates were attributed to a change in the in-built electric field caused by strain relaxation, but in this case our X-ray measurements eliminate this as the reason for the effects of the prelayers. To understand the observed effects, the conduction band (CB) and valence band (VB) profiles in all the samples, shown in Figure 3, were calculated using a commercially available device simulator (nextnano 3 ).…”

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confidence: 93%

The effects of Si-doped prelayers on the optical properties of InGaN/GaN single quantum well structures

Davies

Dawson

Massabuau

et al. 2014

Applied Physics Letters

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Articles you may be interested inInfluence of quantum-confined Stark effect on optical properties within trench defects in InGaN quantum wells with different indium content Quantum-confined stark effect in localized luminescent centers within InGaN/GaN quantum-well based light emitting diodesIn this paper, we report on the effects of including Si-doped (In)GaN prelayers on the low temperature optical properties of a blue-light emitting InGaN/GaN single quantum well. We observed a large blue shift of the photoluminescence peak emission energy and significant increases in the radiative recombination rate for the quantum well structures that incorporated Si-doped prelayers. Simulations of the variation of the conduction and valence band energies show that a strong modification of the band profile occurs for the quantum wells on Si-doped prelayers due to an increase in strength of the surface polarization field. The enhanced surface polarization field opposes the builtin field across the quantum well and thus reduces this built-in electric field. This reduction of the electric field across the quantum well reduces the Quantum Confined Stark Effect and is responsible for the observed blue shift and the change in the recombination dynamics. V C 2014 AIP Publishing LLC. [http://dx.

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confidence: 93%

The effects of Si-doped prelayers on the optical properties of InGaN/GaN single quantum well structures

Davies

Dawson

Massabuau

et al. 2014

Applied Physics Letters

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“…They tentatively ascribe the increased electron capture efficiency to the variation of the potential field distribution in the quantum wells. Later on, Li et al conclude that the InGaN insertion layer can reduce the internal electric field in the quantum well through observing the wavelength blueshift of the cathodoluminescence (CL) spectra and a reduced carrier lifetime derived from the time‐resolved CL spectra . More importantly, Li et al, by the electron holography, also measure and show a reduced electrostatic potential for the LED device with the InGaN insertion layer .…”

Section: Approaches For Improving the Internal Quantum Efficiencymentioning

confidence: 99%

“…Later on, Li et al conclude that the InGaN insertion layer can reduce the internal electric field in the quantum well through observing the wavelength blueshift of the cathodoluminescence (CL) spectra and a reduced carrier lifetime derived from the time‐resolved CL spectra . More importantly, Li et al, by the electron holography, also measure and show a reduced electrostatic potential for the LED device with the InGaN insertion layer . However, a most recent physical model has been developed by Ni et al , Zhang et al , Li et al , Avrutin et al , Zhang et al , and Chang et al that a reduced electron leakage is caused by the phonon‐electron scattering taking place in the InGaN insertion layer.…”

Section: Approaches For Improving the Internal Quantum Efficiencymentioning

confidence: 99%

On the internal quantum efficiency for InGaN/GaN light-emitting diodes grown on insulating substrates

Zhang

et al. 2016

Phys. Status Solidi A

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The internal quantum efficiency (IQE) for InGaN/GaN light‐emitting diodes (LEDs) grown on [0001] sapphire substrates is strongly affected by various factors including polarization effect in the InGaN/GaN multiple quantum wells (MQWs), insufficient electron and hole injections, low p‐type GaN doping efficiency, carrier loss due to the Auger recombination, and current crowding effect especially for the hole current in the p‐GaN region. In this work, the remedies taken by the scientific community to enhance the IQE are reviewed, compared and summarized. Meanwhile, this review also discusses alternative ways including polarization self‐screening effect, polarization cooling, hole accelerator, and hole modulator. The structural solutions we propose in this work can better improve the device performance without increasing the processing difficulty significantly, and their effectiveness in improving the IQE is further supported by the numerical and experimental studies. For example, on the contrary to common belief, the polarizations in the [0001] oriented InGaN/GaN LEDs can be advantageously used to improve the device performance based on our designs.

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“…Typical prelayer structures consist of 20-30 nm of intentionally Si-doped (In)GaN, which can be either a single layer or a short-period superlattice, positioned a few nanometers beneath the 1st QW. The improvements in IQE have been attributed to either increases in the radiative recombination rate 15,16,18,20,21 or decreases in the nonradiative recombination rate. 11,19 Nanhui et al 15,16 reported that the inclusion of an unintentionally doped 20 nm thick In 0.08 Ga 0.92 N layer in an InGaN/GaN multiple QW structure led to an increase in the photoluminescence (PL) intensity at room temperature.…”

Section: Introductionmentioning

confidence: 99%

“…As the internal quantum efficiency (IQE) is determined by competition between radiative and non-radiative recombination processes, slower radiative recombination rates can limit the IQE. It has been reported [10][11][12][13][14][15][16][17][18][19] that the inclusion of an InGaN layer prior to the deposition of the 1st QW, a so-called "prelayer," can lead to significant improvements in the IQE of InGaN multiple QW structures and LEDs. Typical prelayer structures consist of 20-30 nm of intentionally Si-doped (In)GaN, which can be either a single layer or a short-period superlattice, positioned a few nanometers beneath the 1st QW.…”

Section: Introductionmentioning

confidence: 99%

A comparison of the optical properties of InGaN/GaN multiple quantum well structures grown with and without Si-doped InGaN prelayers

Davies

Hammersley

Massabuau

et al. 2016

Journal of Applied Physics

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In this paper, we report on a detailed spectroscopic study of the optical properties of InGaN/GaN multiple quantum well structures, both with and without a Si-doped InGaN prelayer. In photoluminescence and photoluminescence excitation spectroscopy, a 2nd emission band, occurring at a higher energy, was identified in the spectrum of the multiple quantum well structure containing the InGaN prelayer, originating from the first quantum well in the stack. Band structure calculations revealed that a reduction in the resultant electric field occurred in the quantum well immediately adjacent to the InGaN prelayer, therefore leading to a reduction in the strength of the quantum confined Stark effect in this quantum well. The partial suppression of the quantum confined Stark effect in this quantum well led to a modified (higher) emission energy and increased radiative recombination rate. Therefore, we ascribed the origin of the high energy emission band to recombination from the 1st quantum well in the structure. Study of the temperature dependent recombination dynamics of both samples showed that the decay time measured across the spectrum was strongly influenced by the 1st quantum well in the stack (in the sample containing the prelayer) leading to a shorter average room temperature lifetime in this sample. The room temperature internal quantum efficiency of the prelayer containing sample was found to be higher than the reference sample (36% compared to 25%) which was thus attributed to the faster radiative recombination rate of the 1st quantum well providing a recombination pathway that is more competitive with nonradiative recombination processes.

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The effect of InGaN underlayers on the electronic and optical properties of InGaN/GaN quantum wells

Cited by 20 publications

References 14 publications

The effects of Si-doped prelayers on the optical properties of InGaN/GaN single quantum well structures

The effects of Si-doped prelayers on the optical properties of InGaN/GaN single quantum well structures

On the internal quantum efficiency for InGaN/GaN light-emitting diodes grown on insulating substrates

A comparison of the optical properties of InGaN/GaN multiple quantum well structures grown with and without Si-doped InGaN prelayers

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