Effects of surface treatment using aqua regia solution on the change of surface band bending of p-type GaN

Kim, Jong Kyu; Kim, Ki-Jeong; Kim, Jae Nam; Kwak, Joon Seop; Park, Yong Jo; Lee, Jong‐Lam; Kim, Bongsoo

doi:10.1007/s11664-001-0005-3

Cited by 38 publications

(5 citation statements)

References 16 publications

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“…The values were −0.59 V versus RHE and −0.62 V versus RHE for the CaTaO 2 N and CaTaO 2 N-A samples, respectively. Lee et al reported a change of surface band bending of p-type GaN after aqua regia treatment. This behavior could also apply for the acid-treated CaTaO 2 N particles.…”

Section: Resultsmentioning

confidence: 99%

Exploring the Origins of Improved Photocurrent by Acidic Treatment for Quaternary Tantalum-Based Oxynitride Photoanodes on the Example of CaTaO₂N

Jaworski

George

et al. 2019

J. Phys. Chem. C

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Quaternary tantalum-based oxynitrides ATa(O,N) 3 , with electronic band gaps between 1.8 and 2.4 eV, are promising materials for photochemical water-splitting. The tailoring of their surface properties is a critical aspect to obtain efficient hole extraction. We report on the origin of improved photoelectrochemical (PEC) water oxidation by means of acidic treatment for this class of compounds on the example of cubic CaTaO 2 N particles. We address the effect of acidic treatment by using complementary physical characterization techniques, such as X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, 1 H and 14 N solid-state nuclear magnetic resonance (NMR) spectroscopy, electron microscopy, and electronic band structure calculations at the density functional theory level. In combination with PEC measurements, solid-state NMR indicates that the restructured surface displays a meaningfully higher concentration of terminating OH groups. Subsequent deposition of a nickel borate (NiB i ) catalyst on the acid-treated surface yields a higher percentual upsurge of photocurrent in comparison to pristine CaTaO 2 N. Our results highlight the application of solid-state NMR spectroscopy for understanding the semiconductor−catalyst interface in photochemical devices.

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Section: Resultsmentioning

confidence: 99%

Exploring the Origins of Improved Photocurrent by Acidic Treatment for Quaternary Tantalum-Based Oxynitride Photoanodes on the Example of CaTaO₂N

Jaworski

George

et al. 2019

J. Phys. Chem. C

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“…Devices with Pd/Au contacts were then fabricated using standard procedures. First, the samples were immersed in 3:1 mixture of boiling HCl:HNO 3 for 30 min to remove the indium and surface oxide layer [11]. A pattern was applied using photoresist which included circular contacts with a 40 μm radius.…”

Section: Methodsmentioning

confidence: 99%

Demonstration of low resistance ohmic contacts to p-type (202̄1̄) GaN

Yonkee

Leonard

DenBaars

et al. 2015

Semicond. Sci. Technol.

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We demonstrate low resistance Ohmic contacts to (202 ¯1 ¯) semipolar p-type GaN using a thin p ++ -GaN contact layer. This layer was optimized by varying the V/III ratio, Cp 2 Mg flow, thickness, and growth rate which produced low forward voltage devices with specific contact resistivities estimated to be 4 × 10 −4 Ω cm 2 and 5 × 10 −4 Ω cm 2 for palladium contacts and indium tin oxide (ITO) contacts respectively. Forward voltages of 2.89 V and 3.47 V were obtained at 20 A cm −2 and 800 A cm −2 respectively for light emitting diodes (LEDs) emitting at 435 nm with palladium contacts. LEDs with ITO contacts had forward voltages of 2.94 V and 3.55 V at 20 A cm −2 and 800 A cm −2 respectively.

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“…For n-type GaN, it is easy to obtain low resistance ohmic contact (<10 −5 cm 2 ) by using Ti/Al, Ti/Au and Ti/Al/Ti/Au metal schemes. However, it is difficult to achieve such low contact resistivity to p-type GaN because of the low hole concentrations in p-type GaN and high Schottky barrier height at metal/p-type GaN interfaces [5]. In order to achieve low contact resistivity to p-type GaN, a number of research groups have investigated possible solutions, such as chemical treatment of p-GaN surface [5][6][7][8], choosing different metal schemes [9][10][11][12], inserting a thin InGaN capping layer to control the surface polarization field [13] and inserting a thin excessive Mg doping capping layer [2,4,14].…”

Section: Introductionmentioning

confidence: 99%

“…However, it is difficult to achieve such low contact resistivity to p-type GaN because of the low hole concentrations in p-type GaN and high Schottky barrier height at metal/p-type GaN interfaces [5]. In order to achieve low contact resistivity to p-type GaN, a number of research groups have investigated possible solutions, such as chemical treatment of p-GaN surface [5][6][7][8], choosing different metal schemes [9][10][11][12], inserting a thin InGaN capping layer to control the surface polarization field [13] and inserting a thin excessive Mg doping capping layer [2,4,14]. Currently, excessive Mg doping capping layer is widely used in the GaN-based semiconductor because of its good reproducibility, process simplicity and excellent contact properties [3].…”

Section: Introductionmentioning

confidence: 99%

Effects of thin heavily Mg-doped GaN capping layer on ohmic contact formation of p-type GaN

Zhao

Jiang

et al. 2013

Semicond. Sci. Technol.

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The growth condition of thin heavily Mg-doped GaN capping layer and its effect on ohmic contact formation of p-type GaN were investigated. It is confirmed that the excessive Mg doping can effectively enhance the Ni/Au contact to p-GaN after annealing at 550 • C. When the flow rate ratio between Mg and Ga gas sources is 6.4% and the layer width is 25 nm, the capping layer grown at 850 • C exhibits the best ohmic contact properties with respect to the specific contact resistivity (ρ c ). This temperature is much lower than the conventional growth temperature of Mg-doped GaN, suggesting that the deep-level-defect induced band may play an important role in the conduction of capping layer.

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Effects of surface treatment using aqua regia solution on the change of surface band bending of p-type GaN

Cited by 38 publications

References 16 publications

Exploring the Origins of Improved Photocurrent by Acidic Treatment for Quaternary Tantalum-Based Oxynitride Photoanodes on the Example of CaTaO₂N

Exploring the Origins of Improved Photocurrent by Acidic Treatment for Quaternary Tantalum-Based Oxynitride Photoanodes on the Example of CaTaO₂N

Demonstration of low resistance ohmic contacts to p-type (202̄1̄) GaN

Effects of thin heavily Mg-doped GaN capping layer on ohmic contact formation of p-type GaN

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Effects of surface treatment using aqua regia solution on the change of surface band bending of p-type GaN

Cited by 38 publications

References 16 publications

Exploring the Origins of Improved Photocurrent by Acidic Treatment for Quaternary Tantalum-Based Oxynitride Photoanodes on the Example of CaTaO2N

Exploring the Origins of Improved Photocurrent by Acidic Treatment for Quaternary Tantalum-Based Oxynitride Photoanodes on the Example of CaTaO2N

Demonstration of low resistance ohmic contacts to p-type (202̄1̄) GaN

Effects of thin heavily Mg-doped GaN capping layer on ohmic contact formation of p-type GaN

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Exploring the Origins of Improved Photocurrent by Acidic Treatment for Quaternary Tantalum-Based Oxynitride Photoanodes on the Example of CaTaO₂N

Exploring the Origins of Improved Photocurrent by Acidic Treatment for Quaternary Tantalum-Based Oxynitride Photoanodes on the Example of CaTaO₂N