Direct determination of doping concentration and built-in voltage from extraction current transients

Sandberg, Oskar J.; Nyman, Mathias; Österbacka, Ronald

doi:10.1016/j.orgel.2014.09.027

Cited by 30 publications

(61 citation statements)

References 33 publications

(56 reference statements)

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“…(13) and (16) due to improper accounting of Δσ EL . Although this factor of 1=2 was recently noticed by Sandberg et al [80] for the CELIV model described above, the origin of this term was not discussed. The issue arises from attributing the second term in Eq.…”

Section: B Determination Of the Average Carrier Concentration With Cmentioning

confidence: 83%

“…2(a)]. Lorrmann et al [44] and Sandberg et al [80] later presented an excellent analysis of the mathematical implications of this CELIV model using the same original assumptions and equations as Juska et al [43],…”

Section: B Determination Of the Average Carrier Concentration With Cmentioning

confidence: 99%

“…Schottky junctions under the full-depletion assumption are well approximated by this model through a finite initial steady-state depletion width, w [ Fig. 2(a)] [80].…”

Section: B Determination Of the Average Carrier Concentration With Cmentioning

confidence: 99%

“…where dqn meas;CELIV ¼ R t tr 0 ½JðtÞ − U R ϵ=ddt is the apparent initial carrier concentration in the Juska et al [43] model, obtained by integrating the CELIV transient with U R ϵ=d subtracted away and lð0Þ ¼ w as the initial steady-state depletion width [80]. Thus, we see that integrating a CELIV transient in this model over the total evacuation time t tr gives at most half of the actual mobile charges extracted, which is in exact agreement with Eq.…”

Section: B Determination Of the Average Carrier Concentration With Cmentioning

confidence: 99%

See 3 more Smart Citations

Theory of Current Transients in Planar Semiconductor Devices: Insights and Applications to Organic Solar Cells

2015

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Time-domain current measurements are widely used to characterize semiconductor material properties, such as carrier mobility, doping concentration, carrier lifetime, and the static dielectric constant. It is therefore critical that these measurements be theoretically understood if they are to be successfully applied to assess the properties of materials and devices. In this paper, we derive generalized relations for describing current-density transients in planar semiconductor devices at uniform temperature. By spatially averaging the charge densities inside the semiconductor, we are able to provide a rigorous, straightforward, and experimentally relevant way to interpret these measurements. The formalism details several subtle aspects of current transients, including how the electrode charge relates to applied bias and internal space charge, how the displacement current can alter the apparent free-carrier current, and how to understand the integral of a charge-extraction transient. We also demonstrate how the formalism can be employed to derive the current transients arising from simple physical models, like those used to describe charge extraction by linearly increasing voltage (CELIV) and time-of-flight experiments. In doing so, we find that there is a nonintuitive factor-of-2 reduction in the apparent free-carrier concentration that can be easily missed, for example, in the application of charge-extraction models. Finally, to validate our theory and better understand the different current contributions, we perform a full time-domain drift-diffusion simulation of a CELIV trace and compare the results to our formalism. As expected, our analytic equations match precisely with the numerical solutions to the drift-diffusion, Poisson, and continuity equations. Thus, overall, our formalism provides a straightforward and general way to think about how the internal space-charge distribution, the electrode charge, and the externally applied bias translate into a measured current transient in a planar semiconductor device.

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Section: B Determination Of the Average Carrier Concentration With Cmentioning

confidence: 83%

Section: B Determination Of the Average Carrier Concentration With Cmentioning

confidence: 99%

“…Schottky junctions under the full-depletion assumption are well approximated by this model through a finite initial steady-state depletion width, w [ Fig. 2(a)] [80].…”

Section: B Determination Of the Average Carrier Concentration With Cmentioning

confidence: 99%

Section: B Determination Of the Average Carrier Concentration With Cmentioning

confidence: 99%

See 2 more Smart Citations

Theory of Current Transients in Planar Semiconductor Devices: Insights and Applications to Organic Solar Cells

2015

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“…We recently demonstrated that the Charge Extraction by a Linearly Increasing Voltage technique in the doping-induced capacitive regime (doping-CELIV) can be used to determine the built-in voltage and carrier concentration in sandwich-type diode devices 22 . In a uniformly p-doped device a depletion region is formed at the cathode with width w 0 (at an applied steady-state voltage V OFF ) given by:where V bi is the built-in potential and p is the concentration of holes.…”

Section: Introductionmentioning

confidence: 99%

Doping-induced carrier profiles in organic semiconductors determined from capacitive extraction-current transients

Nyman

Sandberg

Dahlström

et al. 2017

Sci Rep

Self Cite

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A method to determine the doping induced charge carrier profiles in lightly and moderately doped organic semiconductor thin films is presented. The theory of the method of Charge Extraction by a Linearly Increasing Voltage technique in the doping-induced capacitive regime (doping-CELIV) is extended to the case with non-uniform doping profiles and the analytical description is verified with drift-diffusion simulations. The method is demonstrated experimentally on evaporated organic small-molecule thin films with a controlled doping profile, and solution-processed thin films where the non-uniform doping profile is unintentional, probably induced during the deposition process, and a priori unknown. Furthermore, the method offers a possibility of directly probing charge-density distributions at interfaces between highly doped and lightly doped or undoped layers.

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Doping Strategies for Tetrasubstituted Paracyclophane Hole Transport Layers in Perovskite Solar Cells

Schulz,

Otterbach,

Tappert

et al. 2024

Adv Funct Materials

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Because of its excellent hole conductivity, p‐doped 2,2′7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenyl‐amine)‐9,9′‐spiro‐bifluorene (spiro‐MeOTAD) is commonly deployed for hole transport in organic metal halide perovskite solar cells, but its rather expensive synthesis prompts the research for alternatives. In this work, tetrasubstituted [2.2]paracyclophanes (PCPs) are synthesized and investigated for replacing spiro‐MeOTAD. To enhance their conductivity, different doping strategies are followed. Best conductivities are achieved by doping PCP thin films with tris(2‐(1H‐pyrazol‐1‐yl)‐4‐tert‐butylpyridine)cobalt(III) tris(bis(trifluoromethylsulfonyl)imide) (FK209), matching the conductivity of state‐of‐the‐art p‐doped spiro‐MeOTAD. Best performance in solar cells is leveraged by doping PCPs with the co‐dopants lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and 4‐tert‐butylpyridine (tBP) which are also used to p‐dope spiro‐MeOTAD thin films in solar cells. Yet, the thermal device stability is maximized upon doping PCPs with FK209 and 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ).

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Direct determination of doping concentration and built-in voltage from extraction current transients

Cited by 30 publications

References 33 publications

Theory of Current Transients in Planar Semiconductor Devices: Insights and Applications to Organic Solar Cells

Theory of Current Transients in Planar Semiconductor Devices: Insights and Applications to Organic Solar Cells

Doping-induced carrier profiles in organic semiconductors determined from capacitive extraction-current transients

Doping Strategies for Tetrasubstituted Paracyclophane Hole Transport Layers in Perovskite Solar Cells

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