Resonant Tunnelling and Intersubband Optical Properties of ZnO/ZnMgO Semiconductor Heterostructures: Impact of Doping and Layer Structure Variation
ZnO-based heterostructures are up-and-coming candidates for terahertz (THz) optoelectronic devices, largely owing to their innate material attributes. The significant ZnO LO-phonon energy plays a pivotal role in mitigating thermally induced LO-phonon scattering, potentially significantly elevating t...
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2024-02-01
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| Online Access: | https://www.mdpi.com/1996-1944/17/4/927 |
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| author | Aleksandar Atić Xizhe Wang Nikola Vuković Novak Stanojević Aleksandar Demić Dragan Indjin Jelena Radovanović |
| author_facet | Aleksandar Atić Xizhe Wang Nikola Vuković Novak Stanojević Aleksandar Demić Dragan Indjin Jelena Radovanović |
| author_sort | Aleksandar Atić |
| collection | DOAJ |
| description | ZnO-based heterostructures are up-and-coming candidates for terahertz (THz) optoelectronic devices, largely owing to their innate material attributes. The significant ZnO LO-phonon energy plays a pivotal role in mitigating thermally induced LO-phonon scattering, potentially significantly elevating the temperature performance of quantum cascade lasers (QCLs). In this work, we calculate the electronic structure and absorption of ZnO/ZnMgO multiple semiconductor quantum wells (MQWs) and the current density–voltage characteristics of nonpolar m-plane ZnO/ZnMgO double-barrier resonant tunnelling diodes (RTDs). Both MQWs and RTDs are considered here as two building blocks of a QCL. We show how the doping, Mg percentage and layer thickness affect the absorption of MQWs at room temperature. We confirm that in the high doping concentrations regime, a full quantum treatment that includes the depolarisation shift effect must be considered, as it shifts mid-infrared absorption peak energy for several tens of meV. Furthermore, we also focus on the performance of RTDs for various parameter changes and conclude that, to maximise the peak-to-valley ratio (PVR), the optimal doping density of the analysed ZnO/Zn<sub>88</sub>Mg<sub>12</sub>O double-barrier RTD should be approximately <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mn>10</mn></mrow><mrow><mn>18</mn></mrow></msup><mo> </mo><msup><mrow><mi mathvariant="normal">c</mi><mi mathvariant="normal">m</mi></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></semantics></math></inline-formula>, whilst the optimal barrier thickness should be 1.3 nm, with a Mg mole fraction of ~9%. |
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| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-07T22:23:16Z |
| publishDate | 2024-02-01 |
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| spelling | doaj.art-e460cd0f93724e18ae047da4ce95e71c2024-02-23T15:25:49ZengMDPI AGMaterials1996-19442024-02-0117492710.3390/ma17040927Resonant Tunnelling and Intersubband Optical Properties of ZnO/ZnMgO Semiconductor Heterostructures: Impact of Doping and Layer Structure VariationAleksandar Atić0Xizhe Wang1Nikola Vuković2Novak Stanojević3Aleksandar Demić4Dragan Indjin5Jelena Radovanović6School of Electrical Engineering, University of Belgrade, Bulevar Kralja Aleksandra 72, 11120 Belgrade, SerbiaSchool of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UKSchool of Electrical Engineering, University of Belgrade, Bulevar Kralja Aleksandra 72, 11120 Belgrade, SerbiaSchool of Electrical Engineering, University of Belgrade, Bulevar Kralja Aleksandra 72, 11120 Belgrade, SerbiaSchool of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UKSchool of Electronic and Electrical Engineering, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UKSchool of Electrical Engineering, University of Belgrade, Bulevar Kralja Aleksandra 72, 11120 Belgrade, SerbiaZnO-based heterostructures are up-and-coming candidates for terahertz (THz) optoelectronic devices, largely owing to their innate material attributes. The significant ZnO LO-phonon energy plays a pivotal role in mitigating thermally induced LO-phonon scattering, potentially significantly elevating the temperature performance of quantum cascade lasers (QCLs). In this work, we calculate the electronic structure and absorption of ZnO/ZnMgO multiple semiconductor quantum wells (MQWs) and the current density–voltage characteristics of nonpolar m-plane ZnO/ZnMgO double-barrier resonant tunnelling diodes (RTDs). Both MQWs and RTDs are considered here as two building blocks of a QCL. We show how the doping, Mg percentage and layer thickness affect the absorption of MQWs at room temperature. We confirm that in the high doping concentrations regime, a full quantum treatment that includes the depolarisation shift effect must be considered, as it shifts mid-infrared absorption peak energy for several tens of meV. Furthermore, we also focus on the performance of RTDs for various parameter changes and conclude that, to maximise the peak-to-valley ratio (PVR), the optimal doping density of the analysed ZnO/Zn<sub>88</sub>Mg<sub>12</sub>O double-barrier RTD should be approximately <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mrow><mn>10</mn></mrow><mrow><mn>18</mn></mrow></msup><mo> </mo><msup><mrow><mi mathvariant="normal">c</mi><mi mathvariant="normal">m</mi></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></semantics></math></inline-formula>, whilst the optimal barrier thickness should be 1.3 nm, with a Mg mole fraction of ~9%.https://www.mdpi.com/1996-1944/17/4/927wide-bandgap oxide semiconductorsresonant tunnellingintersubband transitionsdepolarisation shift |
| spellingShingle | Aleksandar Atić Xizhe Wang Nikola Vuković Novak Stanojević Aleksandar Demić Dragan Indjin Jelena Radovanović Resonant Tunnelling and Intersubband Optical Properties of ZnO/ZnMgO Semiconductor Heterostructures: Impact of Doping and Layer Structure Variation Materials wide-bandgap oxide semiconductors resonant tunnelling intersubband transitions depolarisation shift |
| title | Resonant Tunnelling and Intersubband Optical Properties of ZnO/ZnMgO Semiconductor Heterostructures: Impact of Doping and Layer Structure Variation |
| title_full | Resonant Tunnelling and Intersubband Optical Properties of ZnO/ZnMgO Semiconductor Heterostructures: Impact of Doping and Layer Structure Variation |
| title_fullStr | Resonant Tunnelling and Intersubband Optical Properties of ZnO/ZnMgO Semiconductor Heterostructures: Impact of Doping and Layer Structure Variation |
| title_full_unstemmed | Resonant Tunnelling and Intersubband Optical Properties of ZnO/ZnMgO Semiconductor Heterostructures: Impact of Doping and Layer Structure Variation |
| title_short | Resonant Tunnelling and Intersubband Optical Properties of ZnO/ZnMgO Semiconductor Heterostructures: Impact of Doping and Layer Structure Variation |
| title_sort | resonant tunnelling and intersubband optical properties of zno znmgo semiconductor heterostructures impact of doping and layer structure variation |
| topic | wide-bandgap oxide semiconductors resonant tunnelling intersubband transitions depolarisation shift |
| url | https://www.mdpi.com/1996-1944/17/4/927 |
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