TY - JOUR
T1 - Barrier thickness dependence of the built-in electric field in pseudomorphic ZnO/Zn0.55Mg0.45O multi-quantum wells
AU - Belmoubarik, Mohamed
AU - El Moutaouakil, Amine
N1 - Funding Information:
A.E.M. was supported in part by the United Arab Emirate University UPAR project, grant number 31N393 .
Publisher Copyright:
© 2023 The Authors
PY - 2023/4/25
Y1 - 2023/4/25
N2 - The electric polarization of (Zn, Mg)O alloys, known as stable wide-bandgap semiconductors, is an intrinsic property that has a significant impact on the properties and performance of polar ZnO-based optoelectronic devices, such in the case of the quantum-confined Stark effect. Because Wurtzite (WZ)-ZnMgO exhibits a high potential for epitaxial growth with tunable bandgap energy, we fabricated high-quality pseudomorphic ZnMgO thin films on O-polar ZnO substrates and achieved a maximum Mg solubility of 45%. In addition, the high-quality texture and accurate design of ZnO/ZnMgO multi-quantum wells (MQWs) was confirmed. The electric-polarization-induced built-in electric field (Ein) of polar ZnO/ZnMgO MQWs was examined by using a combination of cryogenic photoluminescence measurements and self-consistent Poisson–Schrödinger method. An electric field of 1.9 MV/cm was obtained for a barrier thickness of 13.6 nm. The barrier-thickness-dependent Ein was fitted with an electrostatic model, and a maximum electric field (Einmax) of 2.4 MV/cm was obtained for a 3.4-nm-thick quantum well. This value was perfectly reproduced by using the crystal parameters of the pseudomorphic ZnMgO epilayer. These results are expected to enhance our understanding of WZ-ZnMgO crystallography and provide a method for the systematic design of polar-ZnO-based optoelectronic devices.
AB - The electric polarization of (Zn, Mg)O alloys, known as stable wide-bandgap semiconductors, is an intrinsic property that has a significant impact on the properties and performance of polar ZnO-based optoelectronic devices, such in the case of the quantum-confined Stark effect. Because Wurtzite (WZ)-ZnMgO exhibits a high potential for epitaxial growth with tunable bandgap energy, we fabricated high-quality pseudomorphic ZnMgO thin films on O-polar ZnO substrates and achieved a maximum Mg solubility of 45%. In addition, the high-quality texture and accurate design of ZnO/ZnMgO multi-quantum wells (MQWs) was confirmed. The electric-polarization-induced built-in electric field (Ein) of polar ZnO/ZnMgO MQWs was examined by using a combination of cryogenic photoluminescence measurements and self-consistent Poisson–Schrödinger method. An electric field of 1.9 MV/cm was obtained for a barrier thickness of 13.6 nm. The barrier-thickness-dependent Ein was fitted with an electrostatic model, and a maximum electric field (Einmax) of 2.4 MV/cm was obtained for a 3.4-nm-thick quantum well. This value was perfectly reproduced by using the crystal parameters of the pseudomorphic ZnMgO epilayer. These results are expected to enhance our understanding of WZ-ZnMgO crystallography and provide a method for the systematic design of polar-ZnO-based optoelectronic devices.
KW - Built-in electric field
KW - Multi-quantum wells
KW - Piezoelectric polarization
KW - Pseudomorphic epitaxy
KW - Zinc oxide
KW - ZnMgO alloy
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U2 - 10.1016/j.jallcom.2023.168960
DO - 10.1016/j.jallcom.2023.168960
M3 - Article
AN - SCOPUS:85146906202
SN - 0925-8388
VL - 941
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
M1 - 168960
ER -