Inversion layer at the interface of Schottky diodes

Demoulin, E.; Wiele, F. Van de

doi:10.1016/0038-1101(74)90031-8

Cited by 16 publications

(11 citation statements)

References 15 publications

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“…The results in Figure a–c, showing the evolution of E F,n and E F,p , match well with results from the device physics literature regarding minority carrier transport through a Schottky contact. − To further verify that our implementation captures the physics of minority carrier transport (a necessary property for modeling SL pseudo-Schottky contacts), we have calculated the injection ratio ( Υ ) in Figure d. It is defined as the ratio of the hole current to the total current ( Υ = | J p |/| J p + J n |) under forward bias .…”

Section: Resultssupporting

confidence: 77%

Simultaneously Solving the Photovoltage and Photocurrent at Semiconductor–Liquid Interfaces

Iqbal

Bevan

2017

J. Phys. Chem. C

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In this work, we present a general theoretical and numerical approach for simultaneously solving the photovoltage and photocurrent at semiconductor−liquid interfaces. Our methodology extends drift-diffusion methods developed for metal−semiconductor Schottky contacts in the device physics community into the domain of semiconductor− liquid "pseudo-Schottky" contacts. This model is applied to the study of photoelectrochemical anodes, utilized in the oxidative splitting of water. To capture both the photovoltage and photocurrent at semiconductor−liquid interfaces, we show that it is necessary to solve both the electron and hole current continuity equations simultaneously. The electron continuity equation is needed to primarily capture the photovoltage formation at photoanodes, whereas the hole continuity equation must be solved to obtain the photocurrent. Both continuity equations are solved through coupled recombination and generation terms. Moreover, to capture charge transfer at the semiconductor−liquid interface, floating (Neumann) boundary conditions are applied to the electron and hole continuity equations. As a model system, we have studied the illuminated hematite photoanode, where it is shown that our approach can capture band flattening during the formation of a photovoltage, as well as the photocurrent onset and saturation. Finally, the utility of this methodology is demonstrated by correlating our theoretical calculations with photocurrent measurements reported in the literature. In general, this work is intended to expand the scope of photocatalytic device design tools and thereby aid the optimization of solar fuel generation.

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Section: Resultssupporting

confidence: 77%

Simultaneously Solving the Photovoltage and Photocurrent at Semiconductor–Liquid Interfaces

Iqbal

Bevan

2017

J. Phys. Chem. C

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“…16 Analytical solutions that more rigorously describe an inversion layer may be provided with additional approximations that consider the effective density of states in the conduction and valence bands with utilization of the Fermi−Dirac distribution. 40,41 The alternative case of semiconductor/electrolyte potential distribution occurs when a semiconductor has redox active surface states within the forbidden bandgap (Figure 4b). Under such conditions, raising the Fermi level from the flat band condition results in Faradaic electron transfer and partial reduction of the surface states.…”

Section: ■ Discussionmentioning

confidence: 99%

Multi-Electron Transfer at H-Terminated p-Si Electrolyte Interfaces: Large Photovoltages under Inversion Conditions

et al. 2023

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Photovoltages for hydrogen-terminated p-Si(111) in an acetonitrile electrolyte were quantified with methyl viologen [1,1′-(CH3)2-4,4′-bipyridinium](PF6)2, abbreviated MV2+, and [Ru(bpy)3](PF6)2, where bpy is 2,2′-bipyridine, that respectively undergo two and three one-electron transfer reductions. The reduction potentials, E°, of the two MV2+ reductions occurred at energies within the forbidden bandgap, while the three [Ru(bpy)3]2+ reductions occurred within the continuum of conduction band states. Bandgap illumination resulted in reduction that was more positive than that measured with a degenerately doped n+-Si demonstrative of a photovoltage, V ph, that increased in the order MV2+/+ (260 mV) < MV+/0 (400 mV) < Ru2+/+ (530 mV) ∼ Ru+/0 (540 mV) ∼ Ru0/– (550 mV). Pulsed 532 nm excitation generated electron–hole pairs whose dynamics were nearly constant under depletion conditions and increased markedly as the potential was raised or lowered. A long wavelength absorption feature assigned to conduction band electrons provided additional evidence for the presence of an inversion layer. Collectively, the data reveal that the most optimal photovoltage, as well as the longest electron–hole pair lifetime and the highest surface electron concentration, occurs when E° lies energetically within the unfilled conduction band states where an inversion layer is present. The bell-shaped dependence for electron–hole pair recombination with the surface potential was predicted by the time-honored SRH model, providing a clear indication that this interface provides access to all four bias conditions, i.e., accumulation, flat band, depletion, and inversion. The implications of these findings for photocatalysis applications and solar energy conversion are discussed.

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“…In that case, the TE component can be suppressed to the extent that it becomes comparable to (or even lower than) the diffusion current. Moreover, as a result of extreme band bending, an inversion layer can be induced at the MS interface, 1,18 which helps in sustaining the minority diffusion current even at high bias. In contrast, in conventional Schottky diodes, the diffusion current will readily be limited by series resistance and/or by a poor supply of minority carriers from the contact.…”

Section: High-barrier Schottky Contacts: Background Informationmentioning

confidence: 99%

Investigation of Pd/MoOx/n-Si diodes for bipolar transistor and light-emitting device applications

Gupta

Thammaiah

Nanver

et al. 2020

Journal of Applied Physics

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Sub-stoichiometric molybdenum oxide (MoO x ) has recently been investigated for application in high efficiency Si solar cells as a "hole selective" contact. In this paper, we investigate the electrical and light-emitting properties of MoO x -based contacts on Si from the viewpoint of realizing functional bipolar devices such as light-emitting diodes (LEDs) and transistors without any impurity doping of the Si surface. We realized diodes on n-type Si substrates using e-beam physical vapor deposition of Pd/MoO x contacts and compared their behavior to implanted p þ n-Si diodes as a reference. In contrast to majority-carrier dominated conduction that occurs in conventional Schottky diodes, Pd/MoO x /n-Si diodes show minority-carrier dominated charge transport with I-V, C-V, and light-emitting characteristics comparable to implanted counterparts. Utilizing such MoO x -based contacts, we also demonstrate a lateral bipolar transistor concept without employing any doped junctions. A detailed C-V analysis confirmed the excessive band-bending in Si corresponding to a high potential barrier (.0:90 V) at the MoO x /n-Si interface which, along with the observed amorphous SiO x (Mo) interlayer, plays a role in suppressing the majority-carrier current. An inversion layer at the n-Si surface was also identified comprising a sheet carrier density greater than 8:6 Â 10 11 cm À2 , and the MoO x layer was found to be conductive though with a very high resistivity in the 10 4 Ω-cm range. We refer to these diodes as metal/non-insulator/semiconductor diodes and show with our device simulations that they can be mimicked as high-barrier Schottky diodes with an induced inversion layer at the interface.

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Inversion layer at the interface of Schottky diodes

Cited by 16 publications

References 15 publications

Simultaneously Solving the Photovoltage and Photocurrent at Semiconductor–Liquid Interfaces

Simultaneously Solving the Photovoltage and Photocurrent at Semiconductor–Liquid Interfaces

Multi-Electron Transfer at H-Terminated p-Si Electrolyte Interfaces: Large Photovoltages under Inversion Conditions

Investigation of Pd/MoOx/n-Si diodes for bipolar transistor and light-emitting device applications

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