Experimental and theoretical analysis of influence of barrier composition on optical properties of GaN/AlGaN multi-quantum wells: Temperature- and pressure-dependent photoluminescence studies
PBN-AR
Instytucja
Instytut Wysokich Ciśnień Polskiej Akademii Nauk
Informacje podstawowe
Główny język publikacji
angielski
Czasopismo
JOURNAL OF ALLOYS AND COMPOUNDS (35pkt w roku publikacji)
ISSN
0925-8388
EISSN
Wydawca
ELSEVIER SCIENCE SA
DOI
URL
Rok publikacji
2018
Numer zeszytu
Strony od-do
1064-1071
Numer tomu
769
Identyfikator DOI
Liczba arkuszy
1,5
Słowa kluczowe
angielski
Semiconductors
Nitride materials
Quantum wells
Recombination
High-pressure
Optical spectroscopy
Streszczenia
Język
angielski
Treść
Studies of internal electric fields in GaN/AlxGa1-xN (3 nm/4 nm) multi-quantum-wells (MQWs) with x = 0.25, 0.5, and 1 are presented. The structures were grown by plasma-assisted molecular-beam epitaxy and characterized by x-ray diffraction, transmission electron microscopy, and secondary ion mass spectroscopy. Optical properties of these structures were investigated by ambient and high-pressure photoluminescence (PL) measurements. They were strongly affected by polarization-induced electric fields giving rise to a quantum confined Stark effect, depending on the composition of the AlGaN barrier. The optical emission energy redshifts by > 100 meV when the Al content in the barrier increases from x = 0.25 up to x = 1, while the pressure coefficients of the PL energy are significantly reduced in comparison with bulk GaN. The transition energies and their pressure dependencies are modelled for tetragonally strained structures with the same geometry using a full tensorial representation of the strain in the MQWs under external pressure. The same MQWs are also simulated using density functional theory calculations. Additionally, influence of blurring of well-barrier interface on transition energy has been modelled. A good agreement between experimental results and theoretical analysis indicates that nonlinear effects induced by the tetragonal strain due to the lattice mismatch between the substrates and the polar MQWs are responsible for a drastic decrease of the pressure coefficients of PL energy, and that these effects are well described by ab initio calculation procedures. Our results reflect the role of composition and geometry on the basic optical properties of nitride quantum wells.
Inne
System-identifier
PX-5b894e2ad5de987508368169
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