Transverse diffusion of minority carriers confined near the GaAs surface plane

Qi, J.; Angerer, W. E.; Ms, Yeganeh; Yodh, AG; Wm, Theis

doi:10.1103/physrevb.51.13533

Cited by 4 publications

(10 citation statements)

References 18 publications

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“…In particular, by tracking the evolution of different interfacial fields contributing to total EFISHG signal we are able to study the redistribution of carriers between the layers due to electron transport across interfaces. Note that the carrier transverse diffusion on GaAs surface plane was demonstrated previously in pump-probe spatially separated SHG experiment [13]. However, to the best of our knowledge, the optical detection of interlayer electron transport in semiconductor heterostructures has not been reported before.…”

mentioning

confidence: 58%

Ultrafast dynamics of interfacial electric fields in semiconductor heterostructures monitored by pump-probe second-harmonic generation

Glinka¹,

Shahbazyan²,

Perakis³

et al. 2002

Applied Physics Letters

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Articles you may be interested inProbing and modeling of interfacial carrier motion in organic devices by optical second harmonic generation J. Vac. Sci. Technol. B 28, C5F12 (2010); 10.1116/1.3454371 Direct probe of the built-in electric field of Mg-doped a -plane wurtzite InN surfaces with time-resolved electricfield-induced second harmonic generation Appl. Phys. Lett. 93, 131106 (2008); 10.1063/1.2979238Electro-optic nature of ultrafast pump-probe reflectivity response from multilayer semiconductor heterostructures

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mentioning

confidence: 58%

Ultrafast dynamics of interfacial electric fields in semiconductor heterostructures monitored by pump-probe second-harmonic generation

Glinka¹,

Shahbazyan²,

Perakis³

et al. 2002

Applied Physics Letters

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“…For instance, the effective diffusion constant near the surfaces is more than 3 orders of magnitude smaller than in the bulk for GaAs. 27 For the PEA-terminated MAPbI 3 microplate shown in Figure 4c−f, the bulk carriers have a D of 1.03 ± 0.01 cm 2 s −1 , similar to that of the reference sample, which confirms that the carrier transport properties of the bulk do not change significantly upon surface functionalization. With a pump photon energy of 3.10 eV, D is measured to be 1.05 ± 0.01 cm 2 s −1 for the nearsurface carriers in the same microplate (Figure 4f), which indicates that the carrier diffusion constant in the near-surface region is fully restored to the bulk value by surface functionalization with PEA cations.…”

Section: Sample Preparation and Surface Characterizationsmentioning

confidence: 79%

“…where D 0 is the diffusion constant for the free carriers, τ t is the average time carriers stay in the traps, and τ f is the time for the carriers to be released from the traps. 27 Overall, PEA surface functionalization can lead to improved optoelectronic devices because of two key factors: the reduced surface trap density and the enhanced in-plane near-surface carrier diffusion. The elimination of surface traps is critical for allowing the carriers to diffuse into the bulk, which is necessary for the function of solar cells.…”

Section: ■ Discussionmentioning

confidence: 99%

“…The diffusion into the bulk can be hindered by factors such as surface recombination, trapping, or band bending. 26,27 While surface recombination generally occurs within a few nanometers of the surface, band bending effects can extend a much longer distance. 26,27 The suppression of carrier diffusion into the bulk in the untreated perovskite crystals is detrimental for the function of solar cells.…”

Section: Sample Preparation and Surface Characterizationsmentioning

confidence: 99%

“…26,27 While surface recombination generally occurs within a few nanometers of the surface, band bending effects can extend a much longer distance. 26,27 The suppression of carrier diffusion into the bulk in the untreated perovskite crystals is detrimental for the function of solar cells. However, this problem can be overcome with PEA functionalization, which facilitates the carriers to diffuse into the bulk (i.e., along the z direction).…”

Section: Sample Preparation and Surface Characterizationsmentioning

confidence: 99%

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Phenethylammonium Functionalization Enhances Near-Surface Carrier Diffusion in Hybrid Perovskites

Wang

Jin

et al. 2020

J. Am. Chem. Soc.

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Understanding semiconductor surface properties and manipulating them chemically are critical for improving their performance in optoelectronic devices. Hybrid halide perovskites have emerged as an exciting class of highly efficient solar materials; however, their device performance could be limited by undesirable surface properties that impede carrier transport and induce recombination. Here we show that surface functionalization of methylammonium lead iodide (MAPbI3) perovskite with phenethylammonium iodide (PEAI), a commonly employed spacer cation in two-dimensional halide perovskites, can enhance carrier diffusion in the near-surface regions and reduce defect density by more than 1 order of magnitude. Using transient transmission and reflection microscopy, we selectively imaged the transport of the carriers near the (001) surface and in the bulk for single-crystal MAPbI3 microplates. The surface functionalization increases the diffusion coefficient of the carriers in the 40 nm subsurface region from ∼0.6 cm2 s–1 to ∼1.0 cm2 s–1, similar to the value for bulk carriers. These results suggest the PEA ligands are effective in reducing surface defect and phonon scattering and shed light on the mechanisms for enhancing photophysical properties and improving solar cell efficiency.

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