Quantum Efficiency of Gallium Nitride–Based Heterostructures with GaInN Quantum Wells
- Moscow Technological University, Institute of Physics and Technology (Russian Federation)
An important parameter of light-emitting heterostructures is their external quantum efficiency. However, another strict requirement for the structures used in fabricating blue and white light-emitting diodes is that the wavelength in the emission spectrum peak and its spread over the entire structure must be 460 ± 5 nm. This is explained primarily by the most frequently used white light-emitting diode design being based on crystals coated with a luminescent layer of a certain composition excited by blue emissions. Deviating from the specified spectral parameters of heterostructures strongly degrades the light and color characteristics of light-emitting diodes. In this work, we solve the problem of optimizing the design and way of growing the active region of an emitting structure consisting of a set of Ga{sub 1 – x}In{sub x}N quantum wells and wider-gap GaN barriers with a certain wavelength in the emission spectrum peak. The variation in the critical thickness of the pseudomorphic layer in the Poisson ratio ranges of 0 to 0.2 for GaAlN and 0 to 0.4 for GaInN is calculated. The emission wavelength is determined by both the bulk Ga{sub 1 – x}In{sub x}N band gap, which depends on the molar fraction of In in quantum wells, and the quantum well thickness in quantum-sized layers. It is found from the obtained dependences that to obtain the required wavelength of 460 nm in the emission spectrum peak, the Ga{sub 1 – x}In{sub x}N layers must be around 10.3% indium and have a quantum well thickness of about 2.5 nm. The effect the In distribution profile in quantum wells has on the external quantum efficiency, the uniformity of the emission wavelength distribution in the spectral peak, and the emission power distribution over the structure is considered. The best results are obtained for a trapezoidal In distribution, since it ensures the narrowest emission wavelength spread in the spectral peak and the most uniform emission power distribution over the structure. Studying the effect the number of quantum wells has on the properties of a heterostructure shows that the maximum external quantum efficiency corresponds to 4 to 5 quantum wells. The highest emission wavelength uniformity in the spectral peak over the structure is obtained at 5 to 7 quantum wells. The optimum number of quantum wells in the active region of the heterostructure is found to be 5.
- OSTI ID:
- 22945134
- Journal Information:
- Semiconductors (Woodbury, N.Y., Print), Vol. 52, Issue 15; Other Information: Copyright (c) 2018 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7826
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
COATINGS
COLOR
CRYSTALS
EMISSION SPECTRA
GALLIUM NITRIDES
INDIUM NITRIDES
LAYERS
LIGHT EMITTING DIODES
LUMINESCENCE
OPTIMIZATION
POISSON RATIO
POWER DISTRIBUTION
QUANTUM EFFICIENCY
QUANTUM WELLS
THICKNESS
WAVELENGTHS