Surface photovoltages due to pulsed sources: Implications for photoemission spectroscopy

Aldao, C. M.; Valtueña, J.F.; Izpura, I.; Muñoz, E.

doi:10.1103/physrevb.50.17729

Cited by 7 publications

(2 citation statements)

References 9 publications

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“…Once the photoconductance gain mechanism in GaN has been described, one needs to relate the impinging photon flux to the photovoltage developed in the SCR. For photons with energy above the band gap, one can assume that all the generated electron-hole pairs are separated by the SCR (or at least this holds for those being generated within a diffusion length [12]). If this was not the case, an efficiency factor could be taken into account in the quantum efficiency η.…”

Section: Gain Dependence On Optical Powermentioning

confidence: 99%

Photoconductive gain modelling of GaN photodetectors

Garrido

Monroy

Izpura

et al. 1998

Semicond. Sci. Technol.

169

134

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A model to explain the behaviour of GaN photoconductive detectors is proposed, and it is based on the idea of a volume modulation rather than a carrier density modulation. Space charge regions inside the semiconductor produce a variation of the conductive volume when carriers are photogenerated. The strong non-exponential photocurrent decays result from carrier capture processes over the barriers associated with space charge regions. By means of computer simulation, this model explains quite well the behaviour of current GaN photoconductor devices and predicts their time response, temperature dependence and responsivity properties.

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Section: Gain Dependence On Optical Powermentioning

confidence: 99%

Photoconductive gain modelling of GaN photodetectors

Garrido

Monroy

Izpura

et al. 1998

Semicond. Sci. Technol.

169

134

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“…Under such illumination we have to consider the effect of the space charge edges associated with (i) the top metal-GaAs Schottky diode, (ii) the bottom n-type GaAs/semiinsulating GaAs homojunction and (iii) the peripheral GaAs/air-surface heterointerfaces, these being negligible from the conductive area viewpoint, since w t. To simplify even more, we will neglect the influence of the bottom n-GaAs/GaAs substrate homojunction. The 10 16 electron-hole pairs created per second will contribute to the photocurrent in the upper Schottky diode [5], thus creating a steady photovoltage V ph , since the diode is in photovoltaic mode (no external load). For an ideal n-GaAs Schottky diode, n = 1 in equation ( 4), using the thermionic theory and a typical barrier height of 0.8 eV [4], one gets a room-temperature saturation current of 2.6 × 10 −8 A cm 2 .…”

Section: Theorymentioning

confidence: 99%

Surface band-bending assessment by photocurrent techniques. Application to III - V semiconductors

Izpura

Valtueña

Muñoz

1997

Semicond. Sci. Technol.

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In epitaxial layers with a large area to thickness ratio, surface and interface space charge regions behave as transverse resistance-capacitance systems modulating the effective volume that takes part in the electrical conductivity. In this work it is shown that in photoconductivity spectroscopy experiments these surface and interface photovoltaic effects can become dominant, therefore giving information about the sample surface and interface band-bending. In photoconductivity spectroscopy, procedures to identify the signatures of such band bending are described. The present technique to assess surface bending is first applied to gated and ungated GaAs samples, to validate the present model. N-type AlGaAs and undoped InGaAs strained buffer layers, with various degrees of strain and surface roughness, are also characterized by this technique.

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