Exciton Effects in Photoconductivity of GaAs

Kravchenko, A.; Nazintsev, V. V.

doi:10.1002/pssb.2221000141

Cited by 4 publications

(1 citation statement)

References 18 publications

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“…Dissociation mechanisms, such as defect assisted dissociation, impact ionization by free carriers, thermal dissociation, and Auger decay in neutral and charged impurities, have been invoked to support the idea of exciton-related photocurrent. 22,23 However, if this were indeed the case, then nanostructures, such as nanowires, wherein the mechanism we propose has no effect, should nonetheless show exciton-related peaks. Examining the literature of photocurrent measurements of, e.g., ZnO and GaN nanowires shows mostly step responses, as expected.…”

Section: Resultsmentioning

confidence: 85%

Double surface effect causes a peak in band-edge photocurrent spectra: a quantitative model

Bick¹,

Shalish²

2016

J. Phys. D: Appl. Phys.

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Band edge photocurrent spectra are typically observed in either of two shapes: a peak or a step.In this study, we show that the photocurrent band edge response of a GaN layer forms a peak, while the same response in GaN nanowires takes the form of a step, both are red-shifted to the actual band edge energy. Although this apparent inconsistency is not limited to GaN, the physics of this phenomenon has been unclear. To understand the physics behind these observations, we propose a model explaining the apparent discrepancy as resulting from a structure-dependent surface-effect. To test the model, we experiment with a GaAs layer showing that we can deliberately switch between a step and a peak. We demonstrate that using this quantitative model one may obtain the exact band edge transition energy, regardless of the red-shift variance, as well as the density of the surface state charges that cause the red shift. The model thus adds quantitative features to photocurrent spectroscopy.

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Section: Resultsmentioning

confidence: 85%