Momentum-resolved electronic structure and band offsets in an epitaxial NbN/GaN superconductor/semiconductor heterojunction

The resistivity and superconducting transition temperature (T c ) of TMNs are dictated by their chemical composition, impurity concentration, and crystal structure. [4] While crystals of most TMNs are stabilized in a cubic rock-salt structure, certain TMNs crystallize in a hexagonal structure. [5] The (111) plane of the cubic lattice of some TMN superconductors possesses only a small lattice mismatch with the (0001) plane of nitride semiconductors. For instance, the lattice mismatches are −0.2% and +0.3% for NbN/AlN [6][7][8] and HfN/GaN, [9] respectively. These structural similarities make the integration of superconductor electronics into semiconductor optoelectronic devices feasible. [10][11][12][13] δ-NbN transitions to the superconducting state at ≈16 K, which is the highest T c among TMNs. It

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“…These structural similarities make the integration of superconductor electronics into semiconductor optoelectronic devices feasible. [ 10–13 ]…”

Section: Introductionmentioning

confidence: 99%

“…These structural similarities make the integration of superconductor electronics into semiconductor optoelectronic devices feasible. [10][11][12][13] δ-NbN transitions to the superconducting state at ≈16 K, which is the highest T c among TMNs. It…”

mentioning

confidence: 99%

Crystal‐Phase Controlled Epitaxial Growth of NbN_x Superconductors on Wide‐Bandgap AlN Semiconductors

Kobayashi

Kihira

Takeda

et al. 2022

Adv Materials Inter

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“…Such applications of SX-ARPES have previously been demonstrated for various semiconductor, oxide, and hybrid heterostructures (see, e.g., Refs. [26,[28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Band bending and k -resolved band offsets at the HfO2/n+(p+)Si interfaces expl

Lev

Strocov

Lebedinskiǐ

et al. 2022

Phys. Rev. Materials

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HfO 2 /Si interface is among the most studied heterostructure materials due to the use of HfO 2 in the mainstream Si microelectronic technology. Following the discovery of new functionalities in HfO 2 such as ferroelectric and reversible resistance-switching properties, we study ultrathin HfO 2 films grown on highly doped (p + and n + ) Si by means of synchrotron-based soft-x-ray spectroscopy techniques, such as x-ray photoelectron spectrosopy (XPS) and angle resolved photoelectron spectroscopy (ARPES). With angular resolution, we directly obtain the electronic dispersions E (k) of the single-crystalline Si substrate in contact with the HfO 2 overlayer, depending on the Si doping and heat treatment, and determine the k-resolved band offset at the interface. Analysis of the Hf and Si core-level energies and line shapes as a function of photon energy yields band bending in HfO 2 and Si. The evolution of the Hf 4 f linewidth upon annealing points to development of a potential distribution across HfO 2 due to charged defects at the surface and interface with Si. The effect of intense x-ray beam on the HfO 2 /Si interfaces, distorting their pristine electronic structure, is evaluated from the time evolution of line shape and position under irradiation. We propose a model explaining the effects of both heat treatment and x-ray irradiation on the HfO 2 /Si electronic structure in terms of oxygen vacancies generated at the surface of HfO 2 and its interface to Si, where the released O atoms react with Si to form SiO x at the interface. The knowledge of the irradiation-dependent band bending is essential for precise determination of the k-dependent band offset locally at the HfO 2 /Si interface.

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“…The sharp band structure obtained in our ARPES measurements suggests that the expected band bending close to the surface is small, not exceeding 200–300 meV, [ 52–55 ] as otherwise it would smear the entire band structure and obscure the observation of clearly dispersing electronic states. This is not surprising since the potential inside the FE may flatten in the proximity of the interface with metallic electrodes or polar adsorbates.…”

Section: Resultsmentioning

confidence: 99%

Experimental Band Structure of Pb(Zr,Ti)O₃: Mechanism of Ferroelectric Stabilization

et al. 2023

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Pb(Zr,Ti)O 3 (PZT) is the most common ferroelectric (FE) material widely used in solid-state technology. Despite intense studies of PZT over decades, its intrinsic band structure, electron energy depending on 3D momentum k, is still unknown. Here, Pb(Zr 0.2 Ti 0.8 )O 3 using soft-X-ray angle-resolved photoelectron spectroscopy (ARPES) is explored. The enhanced photoelectron escape depth in this photon energy range allows sharp intrinsic definition of the out-of-plane momentum k and thereby of the full 3D band structure. Furthermore, the problem of sample charging due to the inherently insulating nature of PZT is solved by using thin-film PZT samples, where a thickness-induced self-doping results in their heavy doping. For the first time, the soft-X-ray ARPES experiments deliver the intrinsic 3D band structure of PZT as well as the FE-polarization dependent electrostatic potential profile across the PZT film deposited on SrTiO 3 and La x SrMn 1−x O 3 substrates. The negative charges near the surface, required to stabilize the FE state pointing away from the sample (P+), are identified as oxygen vacancies creating localized in-gap states below the Fermi energy. For the opposite polarization state (P−), the positive charges near the surface are identified as cation vacancies resulting from non-ideal stoichiometry of the PZT film as deduced from quantitative XPS measurements.

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Momentum-resolved electronic structure and band offsets in an epitaxial NbN/GaN superconductor/semiconductor heterojunction

Abstract: Addressing design of future quantum devices, the study uncovers electronic structure of a superconductor-semiconductor interface.

Cited by 6 publications

References 58 publications

Crystal‐Phase Controlled Epitaxial Growth of NbN_x Superconductors on Wide‐Bandgap AlN Semiconductors

Crystal‐Phase Controlled Epitaxial Growth of NbN_x Superconductors on Wide‐Bandgap AlN Semiconductors

Band bending and k -resolved band offsets at the HfO2/n+(p+)Si interfaces expl

Experimental Band Structure of Pb(Zr,Ti)O₃: Mechanism of Ferroelectric Stabilization

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Momentum-resolved electronic structure and band offsets in an epitaxial NbN/GaN superconductor/semiconductor heterojunction

Abstract: Addressing design of future quantum devices, the study uncovers electronic structure of a superconductor-semiconductor interface.

Cited by 6 publications

References 58 publications

Crystal‐Phase Controlled Epitaxial Growth of NbNx Superconductors on Wide‐Bandgap AlN Semiconductors

Crystal‐Phase Controlled Epitaxial Growth of NbNx Superconductors on Wide‐Bandgap AlN Semiconductors

Band bending and k -resolved band offsets at the HfO2/n+(p+)Si interfaces expl

Experimental Band Structure of Pb(Zr,Ti)O3: Mechanism of Ferroelectric Stabilization

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Crystal‐Phase Controlled Epitaxial Growth of NbN_x Superconductors on Wide‐Bandgap AlN Semiconductors

Crystal‐Phase Controlled Epitaxial Growth of NbN_x Superconductors on Wide‐Bandgap AlN Semiconductors

Experimental Band Structure of Pb(Zr,Ti)O₃: Mechanism of Ferroelectric Stabilization