Band bending near the surface in GaN as detected by a charge sensitive probe

Sabuktagin, S.; Reshchikov, M. A.; Johnstone, D.; Morkoç̌, H.

doi:10.1557/proc-798-y5.39

Cited by 36 publications

(53 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, it is of essential importance to investigate the properties of GBs in impurity-doped n-and p-type semiconductor films. 33,34 Impurity doping of group-III and group-V elements enables us to control the carrier type and conductivity of BaSi 2 experimentally. [35][36][37][38][39] Among them, boron (B) and antimony (Sb) atoms are considered suitable for p-and n-type dopants, respectively, because the carrier concentration can be controlled in a wide range between 10 17 and 10 20 cm À3 at room temperature (RT).…”

mentioning

confidence: 99%

Potential variations around grain boundaries in impurity-doped BaSi2 epitaxial films evaluated by Kelvin probe force microscopy

Tsukahara

Baba

Honda

et al. 2014

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

mentioning

confidence: 99%

Potential variations around grain boundaries in impurity-doped BaSi2 epitaxial films evaluated by Kelvin probe force microscopy

Tsukahara

Baba

Honda

et al. 2014

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…19 Figure 3 also shows the energy-band diagram for the case of depletive chemisorption of an acceptorlike univalent particle on a n-type GaN surface. At the beginning of chemisorption, the upward band bending exists.…”

Section: Resultsmentioning

confidence: 99%

Adsorption and desorption kinetics of Ga on GaN(0001): Application of Wolkenstein theory

et al. 2010

View full text Add to dashboard Cite

The kinetics of Ga adsorption/desorption on GaN͑0001͒ surfaces is investigated over the temperature range of 680-750°C using real-time spectroscopic ellipsometry. The adsorption and desorption kinetics are described in the framework of the Wolkenstein theory, which considers not only the equilibrium between Ga adsorbed on the surface and Ga in the gas phase but also the electronic equilibrium at the surface. It is shown that, because of the fixed polarization charge existing at the GaN͑0001͒ surface, Ga adsorption and desorption processes involve neutral and charged Ga states. By considering the GaN surface charge involved in the surface processes, we demonstrate that a second-order kinetics more accurately describes Ga desorption, in comparison with conventional models, and yields an apparent activation energy of 2.85Ϯ 0.02 eV for Ga desorption consistent with experiments.

show abstract

“…9,[17][18][19] The origin of these electron acceptor surface states is still not well understood. These states may be related to intrinsic defects such as dangling bonds, impurities, surface reconstruction, or random stress, as it is also discussed for other semiconductors.…”

Section: Q Jxmentioning

confidence: 99%

“…9,[17][18][19] The effective surface state capacitance depends on the applied surface treatment. Our observation that the surface defect states are passivated to a large extent upon oxidation is in agreement with Eller et al, who suggested gallium dangling bonds as the origin of surface states.…”

Section: Q Jxmentioning

confidence: 99%

“…In the dark, an upward band bending of approximately 1 eV is expected due to electrons captured by surface states. 9,[17][18][19] Applying a bias in the dark between the GaN sample and a surface contact (electrolytic or metallic) leads to changes of charge density in the SCR and at the surface which results in a change of the band bending. The charge exchange between the SCR and the surface involves hopping of electrons via localized states in the shallow defect band.…”

mentioning

confidence: 99%

See 1 more Smart Citation

GaN surface states investigated by electrochemical studies

Winnerl

Garrido

Stutzmann

2017

Applied Physics Letters

View full text Add to dashboard Cite

We present a systematic study of electrochemically active surface states on MOCVD-grown n-type GaN in aqueous electrolytes using cyclic voltammetry and impedance spectroscopy over a wide range of potentials and frequencies. In order to alter the surface states, the GaN samples are either etched or oxidized, and the influence of the surface treatment on the defect-mediated charge transfer to the electrolyte is investigated. Etching in HCl removes substoichiometric GaO x , and leads to a pronounced density of electrochemically active surface states. Oxidation effectively removes these surface states. Published by AIP Publishing. Recently, group-III nitride materials have attracted considerable interest in fields such as photo-electrochemistry and photocatalysis due to the favorable energy position of their band edges with respect to the redox levels of relevant species in liquid electrolytes. [1][2][3][4][5][6] The flexibility in doping III-nitrides in a controlled way enables the deterministic generation of either holes (for n-type doping) or electrons (for p-type doping) at the surface under illumination to selectively drive oxidation or reduction reactions, respectively. The presence of electronic defect states directly at or close to the semiconductor surface is known to influence charge transfer at semiconductor electrodes. Such electronically active surface defects, e.g., are responsible for surface band bending determining the separation of photo-excited charge carriers and laterally inhomogeneous charging of the surface due to local charge trapping. For a quantitative analysis of the influence of surface states on electrochemical processes and Schottky diodes, it is important to understand the mechanisms governing charge transfer across the GaN surface. In a previous work, 7 we have combined the contact potential difference (CPD) and photoconductivity measurements to investigate electronic processes at or close to illuminated GaN surfaces. We could show that localized surface defect states play a crucial role in the kinetics of photo-generated charges. Sachsenhauser et al. have investigated the charge transfer across the n-type SiC/electrolyte interface. 8 They performed cyclic voltammetry and impedance spectroscopy measurements over a wide range of potentials and frequencies. Adding the ferricyanide/ferrocyanide redox couple to the electrolyte made it possible to reveal the contribution of surface states to the charge transfer and determine the energy distribution of the surface states. In this work, we have investigated whether or not electrically active states located in the GaN band gap are also involved in the charge transfer to an electrolyte. To this end, we have systematically studied the n-type GaN grown by metal-organic chemical vapor deposition (MOCVD) in aqueous electrolytes using cyclic voltammetry and impedance spectroscopy. Different surface treatments are applied in order to alter the surface states and investigate the influence of these on the details of defectmediated charge transfer.(000...

show abstract

Band bending near the surface in GaN as detected by a charge sensitive probe

Cited by 36 publications

References 11 publications

Potential variations around grain boundaries in impurity-doped BaSi2 epitaxial films evaluated by Kelvin probe force microscopy

Potential variations around grain boundaries in impurity-doped BaSi2 epitaxial films evaluated by Kelvin probe force microscopy

Adsorption and desorption kinetics of Ga on GaN(0001): Application of Wolkenstein theory

GaN surface states investigated by electrochemical studies

Contact Info

Product

Resources

About