Photocapacitance spectroscopy of surface states on indium phosphide photoelectrodes

Goodman, C. E.; Wessels, Bruce W.; Ang, P. G. P.

doi:10.1063/1.95251

Cited by 23 publications

(14 citation statements)

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“…51 More compelling is the high density of surface states at 1.2-1.3 eV above the VBM reported for a variety of different chemically treated InP surfaces. [52][53][54] The energetic position of these surface states is in excellent agreement with the pinned position of the Fermi level observed in this work ͑ϳ1.3 eV above the VBM͒. As a result, holes in the valence band of InP would be trapped by the interface states near the Fermi level, and subsequently injected into the HOMO of the adjacent organic layer under applied bias.…”

Section: B Injection From Surface Statessupporting

confidence: 87%

Interfacial electronic structure of a hybrid organic-inorganic optical upconverter device: The role of interface states

Tsai

Helander

2009

Journal of Applied Physics

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Energy-level alignment and charge injection at metal/ C 60 /organic interfaces Appl. Phys. Lett. 95, 043302 (2009); Organic-inorganic hybrid heterojunctions are critical for the integration of organic electronics with traditional Si and III-V semiconductor microelectronics. The amorphous nature of organic semiconductors eliminates the stringent lattice-matching requirements in semiconductor monolithic growth. However, as of yet it is unclear what driving forces dictate the energy-level alignment at hybrid organic-inorganic heterojunctions. Using photoelectron spectroscopy we investigate the energy-level alignment at the hybrid organic-inorganic heterojunction formed between S-passivated InP͑100͒ and several commonly used hole injection/transport molecules, namely, copper phthalocyanine ͑CuPc͒, N , NЈ-diphenyl-N , NЈ-bis-͑1-naphthyl͒-1-1Ј-biphenyl-4,4Ј-diamine ͑␣-NPD͒, and fullerene ͑C 60 ͒. The energy-level alignment at the hybrid organic-inorganic heterojunction is found to be consistent with traditional interface dipole theory, originally developed to describe Schottky contacts. Contrary to conventional wisdom, hole injection from S-passivated InP͑100͒ into an organic semiconductor is found to originate from interface states at or near the Fermi level, rather than from the valance band maximum of the semiconductor. As a result the barrier height for hole injection is defined by the offset between the surface Fermi level of the S-passivated InP͑100͒ and the highest occupied molecular orbital of the organic. This finding sheds new light on the unusual trend in device performance reported in literature for such hybrid organic-inorganic heterojunction devices.

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Section: B Injection From Surface Statessupporting

confidence: 87%

Interfacial electronic structure of a hybrid organic-inorganic optical upconverter device: The role of interface states

Tsai

Helander

2009

Journal of Applied Physics

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“…The Fe presence at the surface has previously been reported to introduce two states, situated at E C Ϫ1.12 eV and E C Ϫ0.79 eV. 14,15 In our case, only the former is observed at room temperature. Low-temperature SPV measurements are expected to yield higher sensitivity to surface charge redistribution.…”

Section: Resultssupporting

confidence: 48%

“…This state is attributed to excess surface P. [11][12][13] The downward slope change at 1.12 eV indicates depopulation of an acceptor state, situated at E C Ϫ1.12 eV, ͑denoted by S 1 ͒ and is attributed to unintentional Fe doping. 14,15 The abrupt upward offset at 1.18 eV was verified to appear due to an optical filter change. The next downward slope change indicates depopulation of an acceptor state, situated at E C Ϫ1.25 eV ͑denoted by A 1 ͒ and attributed to adsorbed O.…”

Section: Methodsmentioning

confidence: 90%

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Surface electronic structure ofp-InP using temperature-controlled surface photovoltage spectroscopy

Kinrot

Shapira

2002

Phys. Rev. B

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Samples of p-InP ͑100͒ have been investigated using temperature-controlled surface photovoltage spectroscopy ͑T-SPS͒, in conjunction with time-resolved photoluminescence and intensity-resolved surface photovoltage measurements. In addition to the previously reported three gap states, attributed to excess surface P, adsorbed O, and Fe unintentional doping, T-SPS reveals a gap state, also attributed to Fe, situated 0.79 eV below the conduction-band minimum. The energy distribution of the latter state has been investigated by measuring its population as a function of temperature and shows good agreement with theory. A direct observation of the spectral blueshift of the InP band gap by T-SPS shows very good agreement with theory.

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“…This study utilizes steady-state photocapacitance spectroscopy (9,10) to characterize the semiconductor electrode/electrolyte interface states, to determine the effect of various surface modifications on these states, and to correlate these results to cell performance. This study utilizes steady-state photocapacitance spectroscopy (9,10) to characterize the semiconductor electrode/electrolyte interface states, to determine the effect of various surface modifications on these states, and to correlate these results to cell performance.…”

Section: Journalmentioning

confidence: 99%

Characterization of Surface States at the InP / Liquid Interface

Goodman¹

1985

J. Electrochem. Soc.

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Photocapacitance spectroscopy of surface states on indium phosphide photoelectrodes

Abstract: Articles you may be interested inReflection anisotropy spectroscopy, surface photovoltage spectroscopy, and contactless electroreflectance investigation of the InP/In0.53Ga0.47As(001) heterojunction system J.

Cited by 23 publications

References 7 publications

Interfacial electronic structure of a hybrid organic-inorganic optical upconverter device: The role of interface states

Interfacial electronic structure of a hybrid organic-inorganic optical upconverter device: The role of interface states

Surface electronic structure ofp-InP using temperature-controlled surface photovoltage spectroscopy

Characterization of Surface States at the InP / Liquid Interface

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