Evidence for nonuniform flow of charge carriers through semiconductor junctions

Tenne, Reshef; Marcu, V.; Yellin, N.

doi:10.1063/1.95104

Cited by 24 publications

(6 citation statements)

References 14 publications

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“…41 Highly nonuniform charge flow induced by ionized defects within a crystalline semiconductor junction is evidenced also in the pitted submicron morphology obtained by photoetching. 42 Due to nonuniformities, an effective area involved in the current transport becomes significantly lower than the geometric area of the metal semiconductor/interface. 43 Technologically, nonuniformity length scales ranging from microns to tens of centimeters can originate from different process steps.…”

Section: Survey Of Mesoscale Nonuniformity Observationsmentioning

confidence: 99%

Random diode arrays and mesoscale physics of large-area semiconductor devices

2004

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Large-area, thin-film semiconductor devices often exhibit strong fluctuations in electronic properties on a mesoscale level that originate from relatively weak microscopic fluctuations in material structures such as grain size, chemical composition, and film thickness. Amplification comes from the fact that electronic transport through potential barriers is exponentially sensitive to the local parameter fluctuations. These effects create new phenomena and establish the physics of large-area, thin-film devices as a distinctive field of its own, quite different from that of microelectronics. We show that ͑i͒ large-area semiconductor thin-film devices are intrinsically nonuniform in the lateral directions, ͑ii͒ the nonuniformity can span length scales from millimeters to meters depending on external drivers such as light intensity and bias, and ͑iii͒ this nonuniformity significantly impacts the performance and stability of, e.g., photovoltaics, liquid crystal displays, and light emitting arrays. From the theoretical standpoint our consideration introduces a new class of disordered systems, which are random diode arrays. We propose a theory describing one class of such arrays and derive a figure of merit that characterizes the significance of nonuniformity effects. Our understanding suggests some methods for blocking the effects of nonuniformities.

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Section: Survey Of Mesoscale Nonuniformity Observationsmentioning

confidence: 99%

Random diode arrays and mesoscale physics of large-area semiconductor devices

2004

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“…In case of the photoanodic etching of the n-GaP crystals at tow light intensities in the potential range of the photocurrent plateau (cases G and H, Table I), the difference in etching morphology between the two polar faces may again be ascribed to the higher rate of hole capture at the (111) face, so that holes at the (111) face have more opportunity to move along the surface and hence to react selectively at places with a higher intrinsic reaction rate. The very dense pattern of micropits at the (lid face might, in analogy to the work of Tenne et al (10)(11)(12), be ascribed to a nonuniform flow of the holes toward the surface. According to Tenne, local electric fields around dopant atoms have to be taken into consideration, resulting in a nonuniform space charge field and hence a nonuniform flow of holes toward the surface.…”

Section: Discussionmentioning

confidence: 58%

“…Etch pits and recessed figures then correspond to sites with high etch rate or carrier supply relative to their surroundings, whereas etch hillocks and elevated figures correspond to sites with a low etch rate or carrier supply relative to their surroundings. Such variations in reaction rate and carrier supply are assumed to occur at dislocation sites, damaged surface sites, and impurity atoms (9)(10)(11)(12)(13).…”

Section: Discussionmentioning

confidence: 99%

On the Factors Determining the Morphology of Wet‐Etched n‐ and p ‐ GaP Single‐Crystal Surfaces

Goossens

Gomes

1991

J. Electrochem. Soc.

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Wet etching of [1 Ill-oriented GaP single crystals is performed in aqueous KOH solutions at different anodic potentials for p-type and at different anodic potentials and illumination levels for n-type samples. Furthermore, both n-and p-type crystals are photoetched in KOBr solutions at open-cricuit potential. The influence of the rate-determining step on the etching morphology is shown. The difference in etching selectivity between the ( 111) and ( 111) face is explained by the different orientation of the Ga-P dipole, resulting in a different reactivity for hole capture. The KOBr photoetch results in the formation of etch hillocks at n-type crystals, whereas etch pits are developed at p-type crystals. This result is explained by the fact that only local variations in the anodic partial current of the process are reflected in the etching morphology.

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“…Surface modification of solid materials by chemical dissolution (etching) reactions has been frequently used to improve their properties for applications such as catalysis, chemical sensing and optoelectronics [1][2][3][4]. Photoelectrochemical etching (photoetching) is a process to modify the surfaces of semiconductor photoelectrodes employing photocorrosion reactions.…”

Section: Introductionmentioning

confidence: 99%