Material properties of graded composition InxGa1−xP buffer layers grown on GaP by organometallic vapor phase epitaxy

Hasenöhrl, S.; Novák, J.; Vávra, I.; Šatka, A.

doi:10.1016/j.jcrysgro.2004.08.044

Cited by 15 publications

(8 citation statements)

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“…Misfit strain is relieved through gliding misfit dislocations and the density of threading dislocations is low. In [7] we have shown that structural properties are influenced not only by structural parameters but also by growth parameters. Two identical buffers prepared using the same growth conditions except of the V/III ratio (80 and 350) exhibited completely different crystallographic structure.…”

Section: Resultsmentioning

confidence: 95%

“…The surface smoothness is influenced by the structure design and by the choice of the growth parameters. Details about the structure design were presented in [7]. We have shown that type of structure investigated in this paper is suitable for use as a buffer.…”

Section: Resultsmentioning

confidence: 98%

“…• C and the growth rate varying from 0.75 µm/h for GaP to 1.26 µm/h for final 1000 nm thick In x Ga 1−x P layer were chosen after the optimization procedure described in [7]. Structures consisted of 300 nm thick GaP followed by eight 300 nm thick In x Ga 1−x P layers.…”

Section: Methodsmentioning

confidence: 99%

“…The layer composition was set up by changing the composition in the gas phase expressed as a ratio of p TMIn /(p TMIn +p TMGa ), where p TMIn and p TMGa are partial pressures of TMIn and TMGa in the reactor. As was described in [7], firstly we calibrated the dependence x In = f p TMIn /(p TMIn + p TMGa ) experimentally, from a set of 1.3 µm thick In x Ga 1−x P single layers prepared directly on GaP and GaAs substrates varying the composition in the gas phase. The layer composition x In was determined by the X-ray diffraction and calculated from the perpendicular lattice mismatch ∆a/a ⊥ assuming that the layer strain is fully relieved.…”

Section: Methodsmentioning

confidence: 99%

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Epitaxial Growth of GaP/InxGa1-xP (xIn ≥ 0.27) Virtual Substrate for Optoelectronic Applications

Hasenöhrl¹,

Novák²,

Vávra³

et al. 2011

Journal of Electrical Engineering

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Compositionally graded epitaxial semiconductor buffer layers are prepared with the aim of using them as a virtual substrate for following growth of heterostructures with the lattice parameter different from that of the substrates available on market (GaAs, GaP, InP or InAs). In this paper we report on the preparation of the step graded InxGa 1−x P buffer layers on the GaP substrate. The final InxGa 1−x P composition x In was chosen to be at least 0.27 . At this composition the InxGa 1−x P band-gap structure converts from the indirect to the direct one and the material of such composition is suitable for application in light emitting diode structures. Our task was to design a set of layers with graded composition (graded buffer layer) and to optimize growth parameters with the aim to prepare strain relaxed template of quality suitable for the subsequent epitaxial growth.K e y w o r d s: crystal structure, organometallic vapor phase epitaxy (OMVPE), semiconducting III-V materials INTRODUCTIONThe excellent properties of blue light emitting diodes (LEDs) based on nitride semiconductor compounds enabled the subsequent developments in solid state lighting. The red side of the visible spectrum is successfully covered with high brightness LED diodes based on (Al x Ga 1−x ) 0.5 In 0.5 P material lattice matched to GaAs. The low efficiency of green sources (so called "green or yellow gap") that are necessary for white and full color applications remains still a problem which has to be solved.One way how to do it is to use InGaN LEDs emitting blue light which is converted down by suitable color converter-phosphor. Such sources can be used for producing white light but they can also emit nearly monochromatic, high-color-purity light [1].Green light LED sources can be also realized on a base of (Al x Ga 1−x ) 0.5 In 0.5 P material lattice matched to GaAs and joined to the optically transparent GaP substrate by wafer bonding technique [2]. For green emission the content of Al has to be higher than 0.3. Increasing the Al content leads to significant decrease in internal radiative recombination efficiency and causes problems with p-type doping [3].Another approach is to prepare the light emitting structure in Al free In x Ga 1−x P ternary alloy deposited directly on GaP substrate. The In x Ga 1−x P alloy exhibits the direct band gap structure (energy gap of 2.24 eV, emission at 554 nm) for the indium content higher than 0.27. The disadvantage of this method is that the lattice parameter of In 0.27 Ga 0.73 P is about a 2.1 % higher than that of GaP substrate. It is necessary to insert between the substrate and the active region an intermediate layer enabling the change of the lattice constant from the substrate to the final active layer. Very important function of this layer is to be able to filter the dislocation propagation to the electroluminescent part of the structure. What is convenient, such graded buffer will be optically transparent for light emitted from LED because of decreasing band-gap with increasing indium content...

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Epitaxial Growth of GaP/InxGa1-xP (xIn ≥ 0.27) Virtual Substrate for Optoelectronic Applications

Hasenöhrl¹,

Novák²,

Vávra³

et al. 2011

Journal of Electrical Engineering

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“…In our previous work we reported on the development of an optically transparent substrate consisted of a GaP substrate, a GaP buffer layer and subsequently deposited In x Ga 1-x P layers with graded value of x In . We found that the final layer with x In = 0.27 may be reached in 8 steps using a grading rate of 10%In/1 µm, a step width of 300 nm, and a growth temperature T g = 740 o C. The optimization process and growth details are described elsewhere [5]. In this work we report on results of photoluminescence and transmission electron microscopy (TEM) characterization of the (Al y Ga 1-y ) 1-x In x P quaternary layers.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence and TEM characterization of (Al_yGa_1–y)_1–xIn_xP layers grown on graded buffers

Novák¹,

Hasenöhrl

Kučera

et al. 2007

Phys. Status Solidi (c)

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Composition, crystallographic quality and low temperature photoluminescence of AlGaInP quaternary layers were studied. These layers were grown on the InGaP/GaP graded buffers by metalorganic vapour phase epitaxy. Final composition of the graded buffer top layer was x In = 0.24. Incorporation of the small amount Al into quaternary led to a substantial improvement of the surface morpohology and crystallographic quality observed in cross-sectional TEM view. Incorporation of higher amount of Al (above 1% ) led to the increase of lattice mismatch, decrease of In content in the alloy and to the indirect band gap.

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Impact of growth conditions on the spatial non‐uniformities of composition in InGaP epitaxial layers

Gregušová¹,

Kučera

Hasenöhrl

et al. 2007

Phys. Status Solidi (c)

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Composition uniformity of InGaP thick epitaxial layers grown on InGaP/GaP graded buffer structure was studied by stepwise wet chemical etching and low temperature photoluminescence. We compared properties of two epitaxial layers grown by MOCVD technique on different graded buffers. Influence of strain and growth condition on the properties of both epitaxial layer was studied and related to the buffer design.

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Material properties of graded composition InxGa1−xP buffer layers grown on GaP by organometallic vapor phase epitaxy

Cited by 15 publications

References 10 publications

Epitaxial Growth of GaP/InxGa1-xP (xIn ≥ 0.27) Virtual Substrate for Optoelectronic Applications

Epitaxial Growth of GaP/InxGa1-xP (xIn ≥ 0.27) Virtual Substrate for Optoelectronic Applications

Photoluminescence and TEM characterization of (Al_yGa_1–y)_1–xIn_xP layers grown on graded buffers

Impact of growth conditions on the spatial non‐uniformities of composition in InGaP epitaxial layers

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Material properties of graded composition InxGa1−xP buffer layers grown on GaP by organometallic vapor phase epitaxy

Cited by 15 publications

References 10 publications

Epitaxial Growth of GaP/InxGa1-xP (xIn ≥ 0.27) Virtual Substrate for Optoelectronic Applications

Epitaxial Growth of GaP/InxGa1-xP (xIn ≥ 0.27) Virtual Substrate for Optoelectronic Applications

Photoluminescence and TEM characterization of (AlyGa1–y)1–xInxP layers grown on graded buffers

Impact of growth conditions on the spatial non‐uniformities of composition in InGaP epitaxial layers

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Photoluminescence and TEM characterization of (Al_yGa_1–y)_1–xIn_xP layers grown on graded buffers