Electrochemical capacitance voltage profiling of the narrow band gap semiconductor InAs

Gopal, V.; Chen, E.-H.; Kvam, E. P.; Woodall, J. M.

doi:10.1007/s11664-000-0134-0

Cited by 14 publications

(5 citation statements)

References 6 publications

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“…11 When the reciprocal square of the capacitance ͑C −2 ͒ increases with a greater reverse bias, then the mobile charge carriers are negative, while a decrease implies p-type carriers. 12 As shown in the inset of Fig. 1, the surface sheet electron density and the spatial distribution of electrons of the unintentionally doped sample as obtained from CV measurements agree well with that observed previously.…”

supporting

confidence: 88%

“…1, the surface sheet electron density and the spatial distribution of electrons of the unintentionally doped sample as obtained from CV measurements agree well with that observed previously. 4 The density and depth are calculated using the standard equations for depletion width, 12 and do not literally reflect the density or thickness of the accumulation layer, as a depletion layer does not begin to form until a reverse bias is sufficient to empty the accumulation layer. Nonetheless, the total amount of charge in the layer can be found from the integral of the capacitance over the applied reverse bias voltage.…”

mentioning

confidence: 99%

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Buried p-type layers in Mg-doped InN

Anderson

Swartz

Carder

et al. 2006

Applied Physics Letters

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Variable magnetic field Hall effect, photoluminescence, and capacitance-voltage ͑CV͒ analysis have been used to study InN layers grown by plasma assisted molecular beam epitaxy. All three techniques reveal evidence of a buried p-type layer beneath a surface electron accumulation layer in heavily Mg-doped samples. Early indications suggest the Mg acceptor level in InN may lie near 110 meV above the valence band maximum. The development of p-type doping techniques offers great promise for future InN based devices.

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supporting

confidence: 88%

mentioning

confidence: 99%

Buried p-type layers in Mg-doped InN

Anderson

Swartz

Carder

et al. 2006

Applied Physics Letters

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“…The geometry of these experiments, in which thermopower is measured parallel to a shallow p-n junction, is uncommon, but has been considered before in the work of Baars et al on HgCdTe (MCT) photodetectors and very recently in the work of Wagener et al on p-type InAs [40][41][42]. The p-InAs study is especially relevant here given that InAs has similar defect properties to InN; the Fermi level is pinned above the conduction band edge at the surface, leading to surface inversion on p-type films and surface electron accumulation on n-type films [42][43][44][45][46]. In both the Baars and Wagener studies, a parallel conduction model is used to explain the observed thermopower of samples with buried p-n junctions parallel to the transport direction.…”

Section: Theory a Seebeck Coefficientmentioning

confidence: 99%

Hole transport and photoluminescence in Mg-doped InN

Miller

Ager

Smith

et al. 2010

Journal of Applied Physics

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Hole conductivity and photoluminescence were studied in Mg-doped InN films grown by molecular beam epitaxy. Because surface electron accumulation interferes with carrier type determination by electrical measurements, the nature of the majority carriers in the bulk of the films was determined using thermopower measurements. Mg concentrations in a "window" from ca. 3 × 10 17 to 1 × 10 19 cm −3 produce hole-conducting, p-type films as evidenced by a positive Seebeck coefficient. This conclusion is supported by electrolyte-based capacitance voltage measurements and by changes in the overall mobility observed by Hall effect, both of which are consistent with a change from surface accumulation on an n-type film to surface inversion on a p-type film. The observed Seebeck coefficients are understood in terms of a parallel conduction model with contributions from surface and bulk regions. In partially compensated films with Mg concentrations below the window region, two peaks are observed in photoluminescence at 672 meV and at 603 meV. They are attributed to band-to-band and band-to-acceptor transitions, respectively, and an acceptor binding energy of ∼70 meV is deduced. In hole-conducting films with Mg concentrations in the window region, no photoluminescence is observed; this is attributed to electron trapping by deep states which are empty for Fermi levels close to the valence band edge. * Corresponding author: JWAger@lbl.gov

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“…This demonstates that surface electron accumulation must be included in interpretations of surface-sensitive spectroscopic and electrical measurements of InN. A similar surface elec-tron accumulation effect was observed in other materials with large electron affinities, such as InAs, 13 which also has its surface E F pinned above its E C . Significant band-gap narrowing due to the band renormalization effect is also evident in this electron accumulation layer.…”

mentioning

confidence: 57%

“…Instead, an electrolyte has been used to form a rectifying contact. 3,4,13 A bias voltage ͑V bias ͒ applied to the electrolyte with respect to the grounded sample bulk shifts the surface Fermi level to E F = E FS + V bias . Thus a negative V bias causes the surface energy bands to move upward relative to E FS , making the surface bands bend less than in Fig.…”

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confidence: 99%

Effects of surface states on electrical characteristics of InN andIn1−xGaxN

Yim

Jones

et al. 2007

Phys. Rev. B

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Surface states are known to pin the Fermi level in InN and In 1−x Ga x N, strongly affecting charge distribution and transport on the surface and at interfaces. By solving Poisson's equation over a range of bias voltages for an electrolyte-based capacitance-voltage measurement configuration, we have calculated the band bending and space charge distribution in this system and developed an electronic model generally applicable to both p-and n-type group-III-nitride thin films. Both conduction band nonparabolicity and band renormalization effects due to the high surface electron concentration were included. The calculated space charge distributions, using the majority dopant concentration as a fitting parameter, are in excellent agreement with experimental data. The model quantitatively describes increasingly strong n-type electrical characteristics on the surface due to electron accumulation in p-type In 1−x Ga x N for decreasing values of x. This also provides a general understanding of the effect of mobile carriers on capacitance-voltage measurements.

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Electrochemical capacitance voltage profiling of the narrow band gap semiconductor InAs

Cited by 14 publications

References 6 publications

Buried p-type layers in Mg-doped InN

Buried p-type layers in Mg-doped InN

Hole transport and photoluminescence in Mg-doped InN

Effects of surface states on electrical characteristics of InN andIn1−xGaxN

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