Heterojunction band discontinuity control by ultrathin intralayers

Niles, David W.; Margaritondo, G.; Perfetti, P.; Capozi, M.

doi:10.1007/978-94-009-3073-5_37

Cited by 3 publications

(4 citation statements)

References 11 publications

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“…Furthermore, three representative samples were measured with PES, using the Ti 2 p 3/2 core level shift with respect to the Fermi level E F ( Fig. 3b inset), providing a direct measure of the built-in potential 12 18 . As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Controlling band alignments by artificial interface dipoles at perovskite heterointerfaces

et al. 2015

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The concept ‘the interface is the device' is embodied in a wide variety of interfacial electronic phenomena and associated applications in oxide materials, ranging from catalysts and clean energy systems to emerging multifunctional devices. Many device properties are defined by the band alignment, which is often influenced by interface dipoles. On the other hand, the ability to purposefully create and control interface dipoles is a relatively unexplored degree of freedom for perovskite oxides, which should be particularly effective for such ionic materials. Here we demonstrate tuning the band alignment in perovskite metal-semiconductor heterojunctions over a broad range of 1.7 eV. This is achieved by the insertion of positive or negative charges at the interface, and the resultant dipole formed by the induced screening charge. This approach can be broadly used in applications where decoupling the band alignment from the constituent work functions and electron affinities can enhance device functionality.

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Section: Resultsmentioning

confidence: 99%

Controlling band alignments by artificial interface dipoles at perovskite heterointerfaces

et al. 2015

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“…There are numerous examples of such effects in different kinds of surfaces and heterointerfaces. Just to give a few examples, formation of an ultra-thin Al intra-layer in ZnSe/Ge heterostructures can increase the valence band offset by more than 0.2 eV [27,28]. Hydrogen was shown to play a crucial role at semiconductor surfaces.…”

Section: Application To the A-si:h/c-si Interfacementioning

confidence: 99%

Band Lineup Theories and the Determination of Band Offsets from Electrical Measurements

Kleider

2012

Physics and Technology of Amorphous-Crystalline Heterostructure Silicon Solar Cells

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Abstract. Semiconductor heterojunctions have been used in the last decades to build devices with enhanced electrical or optoelectrical properties compared to those of equivalent homojunction devices. Examples of heterojunction devices are encountered in laser applications using band gap engineering possibilities in crystalline III-V compounds, and in bipolar transistors in crystalline silicon based electronics. More recently, heterojunctions formed between hydrogenated amorphous silicon (a-Si:H) and crystalline silicon (c-Si) were introduced for the fabrication of silicon solar cells. The main advantage of heterojunctions over homojunctions is due to the band offsets that can provide selective barriers for one type of carriers. The determination of band offsets and band lineup at the interface is thus of crucial importance. A lot of theoretical work has been devoted to this issue. In parallel, various characterization techniques have been developed to provide experimental insight into band offsets. In this chapter the principal models for band lineup at interfaces are recalled, with particular emphasis on Anderson's electron affinity rule and Tersoff's branch-point energy alignment theory. The application to the a-Si:H/c-Si system is discussed. Then, the principal electrical characterization tools based on capacitance and admittance measurements are presented. After a general overview of the widely used capacitance versus bias voltage technique (so-called C-V or 1/C 2 method), the main potential problems and sources of uncertainty when applying this technique to the a-Si:H/c-Si system are addressed. Some features specific to the a-Si:H/c-Si interface are identified and illustrated using both numerical simulations and experimental data. These features are related to the amorphous nature of a-Si:H, e.g. the high density of band gap states, and to the existence of a strong inversion regime at the c-Si surface that can lead to two dimensional electron or hole gases. A simple technique based on the measurement of the planar conductance of a-Si:H/c-Si structures is presented. The determination of band offsets from such measurements and related modelling on both (p) a-Si:H / (n) c-Si and (n) a-Si:H / (p) c-Si structures is discussed. For interfaces used in high efficiency solar cells the band offsets are found to be 0.15 eV for the conduction band and 0.40 eV for the valence band.

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“…Boronitrene and graphene are posed to be future materials in advanced solid state devices. 9,10 Semiconductor heterojunctions was a topic of enormous research activity in the 1980's both experimentally 11 and theoretically, [12][13][14][15] for example, the GaAs/AlAs 14,16,17 and Si/Ge 18,19 interfaces have been very extensively studied. Effects of strain are considered to be important for systems that are lattice mis-matched, as is the case with Si/Ge, that result in substantial atomic relaxations at the interface.…”

Section: Introductionmentioning

confidence: 99%

“…The band offsets of semiconductors can be modified by either doping the interface dipoles or by the deposition of ultra thin interlayers between semiconductors. This modifies the charge distribution creating an interface dipole 11 that results in a relative shifting of the bands.…”

Section: Introductionmentioning

confidence: 99%

Modification of the band offset in boronitrene

2011

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Using density functional methods within the generalized gradient approximation implemented in the Quantum Espresso codes, we modify the band offset in a single layer of boronitrene by substituting a double line of carbon atoms. This effectively introduces a line of dipoles at the interface. We considered various junctions of this system within the zigzag and armchair orientations. Our results show that the "zigzag-short" structure is energetically most stable with a formation energy of 0.502 eV, and with a band offset of 1.51 eV. The "zigzaglong" structure has a band offset of 1.99 eV. The armchair structures are non-polar while the zigzag-single structures show a charge accumulation for the C-substituted B and charge depletion for the C-substituted N at the junction. Consequently there is no shifting of the bands.

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Heterojunction band discontinuity control by ultrathin intralayers

Cited by 3 publications

References 11 publications

Controlling band alignments by artificial interface dipoles at perovskite heterointerfaces

Controlling band alignments by artificial interface dipoles at perovskite heterointerfaces

Band Lineup Theories and the Determination of Band Offsets from Electrical Measurements

Modification of the band offset in boronitrene

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