Spectroscopic XPEEM of highly conductive SI-doped GaN wires

Renault, O.; Morin, Jean‐François; Tchoulfian, Pierre; Chevalier, Nicolas; Feyer, Vitaliy; Pernot, Julien; Schneider, Claus M.

doi:10.1016/j.ultramic.2015.05.007

Cited by 7 publications

(7 citation statements)

References 27 publications

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“…Another effect that needs to be discussed is a surface photovoltage induced by the X-rays. Exposing a p–n junction to an X-ray beam can excite electron–hole pairs, where the resulting electrons and holes in the depletion region will be accelerated into opposite direction, inducing a photocurrent, which in turn can reduce the measured built-in potential. , Nevertheless, the effect of this X-ray-induced surface photovoltage should be of similar size for no external bias and for a small forward or reverse bias; therefore it might affect the measured built-in potential but not significantly the change of the built-in potential under applied bias.…”

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confidence: 99%

Operando Surface Characterization of InP Nanowire p–n Junctions

et al. 2019

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We present an in-depth analysis of the surface band alignment and local potential distribution of InP nanowires containing a p–n junction using scanning probe and photoelectron microscopy techniques. The depletion region is localized to a 15 nm thin surface region by scanning tunneling spectroscopy and an electronic shift of up to 0.5 eV between the n- and p-doped nanowire segments was observed and confirmed by Kelvin probe force microscopy. Scanning photoelectron microscopy then allowed us to measure the intrinsic chemical shift of the In 3d, In 4d, and P 2p core level spectra along the nanowire and the effect of operating the nanowire diode in forward and reverse bias on these shifts. Thanks to the high-resolution techniques utilized, we observe fluctuations in the potential and chemical energy of the surface along the nanowire in great detail, exposing the sensitive nature of nanodevices to small scale structural variations.

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confidence: 99%

Operando Surface Characterization of InP Nanowire p–n Junctions

et al. 2019

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“…To clarify the atomic structure of the Si dopant, the XANES spectra were simulated by using FEFF9 (XANES simulation software). − Based on previous studies, substitutional site (Si replacing Ga) (Sub) and interstitial site (Si is located between Ga atom and N atom) (Inter) were reported as the Si dopant structures in GaN. ,,, Therefore, the XANES spectra for the Sub and Inter sites were simulated. Each simulation employed ∼350 atoms and the final-state effect; that is, the Z + 1 approximation was used in the present simulations. , …”

Section: Results and Discussionmentioning

confidence: 99%

“…Renault et al. investigated atomic structures and chemical states of dopants for Mg-doped GaN using X-ray photoelectron spectroscopy and X-ray diffraction . However, they could not clarify atomic structures and chemical states in active sites of the dopants.…”

Section: Introductionmentioning

confidence: 99%

“…35 Renault et al investigated atomic structures and chemical states of dopants for Mg-doped GaN using X-ray photoelectron spectroscopy and X-ray diffraction. 36 However, they could not clarify atomic structures and chemical states in active sites of the dopants. Thus, we require a method that allows us to probe chemical states and atomic structures of the active and inactive dopants in GaN.…”

Section: Introductionmentioning

confidence: 99%

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Atomic Structures and Chemical States of Active and Inactive Dopant Sites in Si-Doped GaN

Tang

Yamashita

2021

ACS Appl. Electron. Mater.

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The atomic structures and the electronic states of active and inactive dopant sites in semiconductor are elucidated successfully by using X-ray absorption near-edge structure (XANES), Auger electron spectroscopy (AES), and photoelectron spectroscopy (PES). To demonstrate the versatility of this method, we investigated Si-doped GaN as a prototype and clarified the atomic structures and chemical states at the active and inactive dopant sites in GaN. From AES and PES, it was found that Sidoped GaN formed two dopant states, which were attributed to Si 3 N 4 and SiN x . From the Si K-edge XANES, the Si 3 N 4 state did not exhibit electronic states in the GaN bandgap, indicating inactive dopant sites in GaN, whereas the SiN x state exhibited bandgap states. Thus, the SiN x state should act as an active dopant site in Si-doped GaN. The simulated XANES spectra well reproduced the electronic state in the GaN bandgap when the Ga atom is replaced by the Si atom, suggesting that the active dopant site may be the Si-substituted Ga sites.

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“…21,22 Charge exchange with the bulk occurs slowly, with a large time constant, typically of the order of seconds or more, and hence, these states are usually called slow state. 22 Both types are suggested to contribute to surface band bending in GaN near its surface, [21][22][23][24] and they also contribute to the surface photovoltage (SPV), i.e., the change of band bending on illumination. 19,25,26 In the case of n-GaN, this is due to the electric field driven accumulation of photo-generated holes at the surface where they screen the negative surface charges and, thus, reduce the band bending.…”

Section: Introductionmentioning

confidence: 99%

Photo-assisted Kelvin probe force microscopy investigation of three dimensional GaN structures with various crystal facets, doping types, and wavelengths of illumination

Deeb

Ledig

Wei

et al. 2017

Journal of Applied Physics

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Three dimensional GaN structures with different crystal facets and doping types have been investigated employing the surface photo-voltage (SPV) method to monitor illumination-induced surface charge behavior using Kelvin probe force microscopy. Various photon energies near and below the GaN bandgap were used to modify the generation of electron–hole pairs and their motion under the influence of the electric field near the GaN surface. Fast and slow processes for Ga-polar c-planes on both Si-doped n-type as well as Mg-doped p-type GaN truncated pyramid micro-structures were found and their origin is discussed. The immediate positive (for n-type) and negative (for p-type) SPV response dominates at band-to-band and near-bandgap excitation, while only the slow process is present at sub-bandgap excitation. The SPV behavior for the semi-polar facets of the p-type GaN truncated pyramids has a similar characteristic to that on its c-plane, which indicates that it has a comparable band bending and no strong influence of the polarity-induced charges is detectable. The SPV behavior of the non-polar m-facets of the Si-doped n-type part of a transferred GaN column is similar to that of a clean c-plane GaN surface during illumination. However, the SPV is smaller in magnitude, which is attributed to intrinsic surface states of m-plane surfaces and their influence on the band bending. The SPV behavior of the non-polar m-facet of the slightly Mg-doped part of this GaN column is found to behave differently. Compared to c- and r-facets of p-type surfaces of GaN-light–emitting diode micro-structures, the m-plane is more chemically stable.

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Spectroscopic XPEEM of highly conductive SI-doped GaN wires

Cited by 7 publications

References 27 publications

Operando Surface Characterization of InP Nanowire p–n Junctions

Operando Surface Characterization of InP Nanowire p–n Junctions

Atomic Structures and Chemical States of Active and Inactive Dopant Sites in Si-Doped GaN

Photo-assisted Kelvin probe force microscopy investigation of three dimensional GaN structures with various crystal facets, doping types, and wavelengths of illumination

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