Carrier Concentration In Semiconductor Research Articles

Reversible Carrier Concentration Control on Ultra-Thin in2O3 By Viologen Molecules Charge Transfer Method

Ultra-thin Oxide semiconductor fabricated by atomic layer deposition (ALD) is one of the promising candidates, due to their ultra-thin thickness and being highly compatible with the silicon process.[1] However, further tuning the oxide semiconductor's carrier concentration is still an interesting issue. Although annealing is a widely used way, the increase in thermal budget is unwilling to be met. To adjust the carrier concentration without increasing the thermal budget, viologen molecule, a strongly n-type dopant which have been successfully applied to different material systems including 2D,[2] CNT,[3] ultra-thin Ⅲ-Ⅴ,[4] has been used in the In2O3 transistor(as shown in Figure 1a). After viologen treatment, the viologen dopants increased the carrier concentration and caused a difference of n 2D, which is 2 × 1012 cm-2 of 2 nm thickness in In2O3, without degrading the mobility under the same overdrive voltage. The In2O3 transistor achieves an electron sheet density of 6.8 × 1012 cm−2. To further expand the function, viologen dopants are modified by hydroxy group. With hydroxy group modifying, the viologen dopants can be removed by acetone and be re-treated back on the In2O3 again. The reversible cycle of viologen treatment can be repeated multiple times without harming the In2O3 device (as shown in Figure 1b). Precise control of the threshold voltage allows for fine-tuning of the transistor between depletion mode and enhancement mode. Based on this, a depletion load inverter has been demonstrated. This result shows that the viologen dopants and In2O3 have the potential to be further integrated with other low dimensional materials in BEOL without raising the thermal budget while tuning the carrier concentrations. Figure 1. a) Schematic representation of the structure of a In2O3 bottom-gate transistor and the viologen charge transfer process. b) The transfer characteristics of In2O3 transistors repeatedly treated and removed of OHV for four cycles. References (1) Si, M.; Lin, Z.; Chen, Z.; Sun, X.; Wang, H.; Ye, P. D. Scaled Indium Oxide Transistors Fabricated Using Atomic Layer Deposition. Nat. Electron. 2022, 5 (3), 164-170. DOI: 10.1038/s41928-022-00718-w.(2) Kiriya, D.; Tosun, M.; Zhao, P.; Kang, J. S.; Javey, A. Air-Stable Surface Charge Transfer Doping of MoS2 by Benzyl Viologen. J. Am. Chem. Soc. 2014, 136 (22), 7853-7856. DOI: 10.1021/ja5033327.(3)Kim, S. M.; Jang, J. H.; Kim, K. K.; Park, H. K.; Bae, J. J.; Yu, W. J.; Lee, I. H.; Kim, G.; Loc, D. D.; Kim, U. J.; Lee, E.-H.; Shin, H.-J.; Choi, J.-Y.; Lee, Y. H. Reduction-Controlled Viologen in Bisolvent as an Environmentally Stable n-Type Dopant for Carbon Nanotubes. J. Am. Chem. Soc. 2009, 131 (1), 327-331. DOI: 10.1021/ja807480g.(4) Takei, K.; Kapadia, R.; Li, Y.; Plis, E.; Krishna, S.; Javey, A. Surface Charge Transfer Doping of III–V Nanostructures. J. Phys. Chem. C 2013, 117 (34), 17845-17849. Figure 1

Precision assessment of carrier concentration in semiconductors with negative electron affinity

Precision assessment of carrier concentration in semiconductors with negative electron affinity

An Expansion of Polarization Control Using Semiconductor-Liquid Junctions.

This report examines the concept of independent control over current and applied potential in electrocatalysis, as a means of improving control over product selectivity. Previous work, while permitting separate modulation of current and potentiostat bias, precluded independent control over the current flow and applied cell potential. This study seeks to resolve that limitation by exploiting the Schottky diode behavior inherent to semiconductor-electrolyte interfaces. Light is explored as a prospective second degree of freedom for controlling polarization in a suitably designed, photoelectrochemical (PEC) device, enabling the arbitrary selection of current with respect to an applied cell potential. In contrast to metal electrodes, the property of light-dependent carrier concentrations in semiconductors forms the operative means of controlling charge fluxes at some arbitrary applied potential in PEC devices featuring a semiconductor-liquid junction. This functionality enables exploration of polarization states distinct from those accessible with a dark cell, with implications for improved control over electrochemical reactions.

Electrical conductivity and corrosion resistance of Mo/Ti/Mn-based composite conversion films on AZ91D magnesium alloy

In this reported study, conductive composite conversion films on an AZ91D magnesium alloy were prepared by adding Ga3+ to a deposition solution that contained molybdenum, titanium and manganese ions. The Ga3+ significantly improved the conductivity and corrosion resistance of the resulting films. The electrical contact resistance (ECR) of the Molybdenum/Titanium/Manganese (MTM) film decreased from 0.436 Ω/in2 to 0.106 Ω/in2 at 200 psi when Ga3+ was added to form the Molybdenum-Titanium-Manganese-Gallium (MTMG) film. In addition, the polarization resistance of the Ga3+ amended film increased from 633.1 Ω·cm2 to 1930.835 Ω·cm2, MTMG showed obvious passivation behavior. The Ga3+ doping appeared to increase the carrier concentration and narrow the band gap of the semiconductor film. The N-type semiconductor carrier concentration increased from 2.11 × 1019 cm−3 to 7.052 × 1019 cm−3 in the MTMG film vs the MTM film. The P-type semiconductor carrier concentration in the MTMG film increased from 2.727 × 1018 cm−3 to 3.480 × 1019 cm−3 compared to the MTM film. The MTM band gap decreased from 2.916 eV to 2.714 eV in the MTMG film, which was attributed to the cross-doping of Ga3+ with transition metals in the MTMG material. The MTMG film had a three-layer structure, which preferentially formed a thin film on the β-phase and subsequently grew layer by layer.

Self-organization dynamics of charge carrier concentration in semiconductors due to the charge injection

The purpose of this study is to investigate the phenomenon of self-organization of the dynamics of charge carriers in semiconductor structures. Investigate the basic model, give a numerical estimate for given parameters and propose its modification. Determine the dependence of the evaluation results on the control parameter. Consider the dynamics when the control parameter depends on time. Carry out theoretical analysis, numerical simulation and build graphs. Methods. In this paper, we investigate the possibilities and limitations of the basic model of generation-recombination dynamics in semiconductors, proposed earlier by other researchers. A modification of this model was proposed and considered. Results. Various types of charge carrier concentration dynamics are demonstrated.Theoretical analysis of the model was carried out. Numerical simulation has shown that for certain values of the control parameter, stable states are observed. Numerical estimates of the control parameter were obtained, phase portraits of the nonlinear equation were constructed, and the behavior of the dynamical system was considered when the control parameter is periodic. The extended model showed a qualitatively new behavior in comparison with the basic one. Conclusion. It is shown that charge dynamics in semiconductor structures can exhibit different behaviors. The patterns and estimates obtained are consistent with those obtained earlier. The results obtained can be verified experimentally and will be useful in the development of photo- and beta-voltaic devices.

Enhanced output performance of ZnO thin film triboelectric nanogenerators by leveraging surface limited ga doping and insulting bulk

Although triboelectric nanogenerator (TENG) has been developed as a new green energy source, the dominant charge transfer mechanism regarding surface chemistry has not been fully uncovered yet, especially in semiconductor materials. Semiconductor materials are technically important not only capable of tuning total carrier concentrations available for charge transfer in TENG, but corresponding optoelectronic properties for applications into tribo-tronics. However, doping renders one serious drawback as tribo-charges tend to leak and cannot be held in place for energy output. In order to prevent carriers from leaking while maintain the characteristics of tunable carrier concentrations in semiconductors, a two-layer structure of Ga-doped ZnO/undoped-ZnO is proposed by a two-step growth methodology. A ZnO thin film was first grown by magnetron sputter followed by Ga doping restricted to a shallow surface region by thermal diffusion treatment in the second step. The results support that surface work function difference between two materials in electrification under the well preservation of tribo-charges retention governs the charge transfer capability responsible for output performance of TENGs, where the output voltage and current of the ZnO film doped with 0.93 at% Ga can be drastically enhanced by 16 and 13 times, respectively. However, β-Ga2O3 forms on the surface when Ga concentration is higher than 0.93 at%. Nevertheless, the even larger work function of β-Ga2O3 than Ga-doped ZnO does not lead to larger output performance, implying that work function difference is not the prime factor but carrier concentration in the conduction band needs to be considered for the performance of TENGs. This work demonstrated a viable method to modify the work function of ZnO only confined to the surface through doping without disturbing the bulk, optimizing the device structure for TENGs based on semiconductor.

Verification of Carrier Concentration-Dependent Behavior in Water-Infiltration-Induced Electricity Generation by Ionovoltaic Effect.

Water-infiltration-induced power generation has the renewable characteristic of generating electrical energy from ambient water. Importantly, it is found that the carrier concentration in semiconductor constituting the energy generator seriously affect the electricity generation. Nevertheless, few studies are conducted on the influence of semiconductor carrier concentration, a crucial factor on electricity generation. Due to this, understanding of the energy harvesting mechanism is still insufficient. Herein, the semiconductor carrier concentration-dependent behavior in water-infiltration-induced electricity generation and the energy harvesting mechanism by ionovoltaic effect are comprehensively verified. A clue to enhance the electric power generation efficiency is also proposed. When 20 µL of water (NaCl, 0.1 m) infiltrates into a porous CuO nanowires film (PCNF), electric power of ≈0.5V and ≈1 µA are produced for 25 min. Moreover, the PCNF shows good practicability by generating electricity using various ambient water, turning on LEDs, and being fabricated as a curved one.

Disorder-induced Anderson-like localization for bidimensional thermoelectrics optimization

Disorder-induced Anderson-like localization for bidimensional thermoelectrics optimization

Disorder-Induced Anderson-Like Localization for Bidimensional Thermoelectrics Optimization

Thermoelectric materials, which can generate electricity from waste heat or be used as solid-state Peltier coolers, couldplay an important role in global sustainable energy. However, improving thermoelectric efficiency has proven difficult, largelydue to the complex interdependence of electronic properties of solids. Early work by Ioffe has developed into the standardthermoelectric optimization paradigm of tuning the electronic carrier concentration in semiconductors. Although the localizationtheory of electrons by Anderson and Mott has developed in parallel, its potential for thermoelectrics optimization has notbeen explored. Here, we show that electron localization induced by structural disorder also provides an effective optimizationstrategy for thermoelectric materials. By using a transport model that includes the relevant physics of localization it is shownthat the maximum thermoelectric figure-of-merit can be increased ~20% by tuning both carrier concentration and disorder.This approach is demonstrated in two model Ge-Sb-Te material systems and confirms that the peak figure-of-merit occursin slightly disordered materials. Particularly for highly degenerate semiconductors this bidimensional optimization strategyprovides a new methodology to attain high thermoelectric performance.

Introduction rates of radiation defects in electron irradiated semiconductor crystals of n-Si and n-GaP

A study was made of the introduction rate of radiation defects ΔNdef/ΔD versus the fast electron irradiation dose (D) in semiconductor crystals of n-Si and n-GaP. We take the concentration of radiation defects concentration Ndef to be the difference between the carrier concentration of semiconductors before n0 and after irradiation n(D) at the dose D, delivered at room temperature. By application of an appropriate fitting function to the dose dependent curves of the Ndef(D), it was demonstrated that the empiric exponential law of the form Ndef=n0(1−exp(−D/D0)) gives the best agreement with the experimental data, irrespective of the electron energy and irradiation dose. D0 is the irradiation dose, at which the carrier concentration n(D) at a temperature T=300K decreases by a factor of e. The results showed that the formation of radiation defects in the samples studied is not a linear process and ΔNdef/ΔD are found to decrease exponentially with increasing irradiation dose, according to their particular character. Using the same fitting method, it was found that for certain samples, beyond a particular radiation dose level, the rate of carrier mobility versus radiation dose also decreased exponentially.

Optical properties of (Se80Te20)100-xZnx (2 ≤ x ≤ 6) amorphous thin films

The (Se80Te20)100-xZnx (2 ≤ x ≤ 6)thin film compositions have been prepared by melt quenching technique followed by electron-beam physical vapour deposition. X-ray diffraction pattern and SEM micrographs ascertain the amorphous nature of prepared thin films. The transmission spectra from UV/VIS/NIR double beam spectrophotometer (500 ≤ λ (nm) ≤ 2600) is used for optical characterization of thin films. The absorption coefficient and energetic parameter (A) for various compositions indicate that the absorption mechanism in Se-Te-Zn glassy system occur via allowed indirect transitions. The optical band gap for thin films lies at the edge of near infrared region in A-band (λ~900 nm).The average heat of atomization has no essential influence on the optical band gap energy values. The refractive index (n) for thin films exhibit normal dispersion in the wavelength range 800 nm ≤ λ ≤ 1100 nm (IR-A), and is nearly constant at longer wavelength λ ≥ 1400 nm (IR-B). The dispersion of refractive index below the band gap energy region is studied using the Wemple-DiDomenico (WDD) single oscillator model. It is found that, to a good approximation the single-oscillator energy scales with the optical band gap (Eo≈1.4Egopt). The deduced value of parameter β = 0.24 ± 0.01 corresponds to ionic character of bonds in the Se-Te-Zn system. The dielectric parameters (ε’, ε”,ɛ∞, ɛL), optical conductivity (σ1,σ2), ratio of carrier concentration to the effective mass (N/m*) have also been deduced for thin films. The calculated values of plasma frequency ωP and Nopt are in good agreement with carrier concentration of semiconductors. The energy loss occurred in the interior of the Se-Te-Zn thin films is found to be due to the interband electronic transitions.

Thermally stable epitaxial ZrN/carrier-compensated Sc0.99Mg0.01N metal/semiconductor multilayers for thermionic energy conversion

Epitaxial metal/semiconductor multilayers are attractive materials for a range of solid-state energy conversion devices. Applications include waste-heat-to-electrical energy conversion, hot-electron-based solar energy conversion in photocatalysis and photodiodes, optical hyperbolic metamaterials, and engineering thermal hyperconductivity. ZrN/ScN is among the first metal/semiconductor multilayer structures to also display promising thermal and electronic properties. However, for efficient thermionic transport, it is necessary to control and tune the Schottky barrier height at the metal/semiconductor interfaces, since this controls current flows across the superlattices’ cross-plane directions. Sputter-deposited semiconducting ScN in ZrN/ScN multilayers contains a high concentration of n-type carriers, primarily due to oxygen impurities. This leads to a very small depletion width at metal/semiconductor interfaces, preventing thermionic transport. To overcome this challenge, the n-type carrier concentration of ScN has been reduced by Mg hole doping to ~ 1.6 × 1018 cm−3. In this article, we report the growth of thermally stable epitaxial ZrN/carrier-compensated Sc0.99Mg0.01N multilayers useful for thermionic emission-based devices. We present carrier concentration and transport regime calculations. Characterization of the microstructure and thermal stability was performed by combining aberration-corrected scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy mapping, and atom probe tomography. The results show stoichiometric Sc0.99Mg0.01N layers with a uniform magnesium concentration, and lattice-matched ZrN/Sc0.99Mg0.01N growth with smooth and atomically sharp interfaces that are thermally stable after 48 h at 950o C. The successful demonstration of thermally stable ZrN/carrier-compensated Sc0.99Mg0.01N multilayers with a semiconductor carrier concentration of 2 × 1018 cm−3 is expected to enable efficient thermionic transport devices with improved properties.

Modulation of propagating surface plasmons

The diffraction limit of light greatly limits the development of conventional optical devices, which are difficult to be miniaturized and integrated with high density. Surface plasmons, electromagnetic modes at the metal-dielectric interface, can concentrate light into deep subwavelength dimensions, enabling the manipulation of light at the nanometer scale. Surface plasmons can be used as information carrier to transmit and process optical signals beyond the diffraction limit. Therefore, nanodevices based on surface plasmons have received much attention. By modulating surface plasmons, the modulation of optical signals at nanoscale can be realized, which is important for the development of on-chip integrated nanophotonic circuits and optical information technology. In this article, we review the modulations of propagating surface plasmons and their applications in nano-optical modulators. The wave vector of propagating surface plasmons is very sensitive to the dielectric function of the metal and the environment. By tuning the dielectric function of the metal and/or the surrounding medium, both the real and imaginary part of the wave vector of surface plasmons can be modified, leading to the modulation of the phase and propagation length of surface plasmons and thereby modulating the intensity of optical signals. We first introduce the basic principles of different types of modulations, including all-optical modulation, thermal modulation, electrical modulation, and magnetic modulation. The all-optical modulation can be achieved by modulating the polarization and phase of input light, pumping optical materials, changing the dielectric function of metal by control light, and manipulating a nanoparticle by optical force to modulate the scattering of surface plasmons. The modulation based on thermal effect depends on thermo-optic materials and phase-change materials, and the temperature change can be triggered by photothermal effect or electrical heating. For electrically controlled modulation, Pockels electro-optic effect and Kerr electro-optic effect can be employed. Electrical modulation can also be realized by controlling the carrier concentration of semiconductors or graphene, using electrochromatic materials, and nanoelectromechanical control of the waveguide. The modulation of surface plasmons by magnetic field relies on magneto-optic materials. We review recent research progresses of modulating propagating surface plasmons by these methods, and analyze the performances of different types of plasmonic modulators, including operation wavelength, modulation depth or extinction ratio, response time or modulation frequency, and insertion loss. Finally, a brief conclusion and outlook is presented.

Enhanced piezoelectric output of NiO/nanoporous GaN by suppression of internal carrier screening

The efficiency of piezoelectric nanogenerators (PNGs) significantly depends on the free carrier concentration of semiconductors. In the presence of a mechanical stress, piezoelectric charges are generated at both ends of the PNG, which are rapidly screened by the free carriers. The screening effect rapidly decreases the piezoelectric output within fractions of a second. In this study, the piezoelectric outputs of bulk- and nanoporous GaN-based heterojunction PNGs are compared. GaN thin films were epitaxially grown on sapphire substrates using metal organic chemical vapor deposition. Nanoporous GaN was fabricated using electrochemical etching, depleted of free carriers owing to the surface Fermi-level pinning. A highly resistive NiO thin film was deposited on bulk- and nanoporous GaN using radio frequency magnetron sputter. The NiO/nanoporous GaN PNG (NPNG) under a periodic compressive stress of 4 MPa exhibited an output voltage and current of 0.32 V and 1.48 μA cm−2, respectively. The output voltage and current of the NiO/thin film-GaN PNG (TPNG) were three and five times smaller than those of the NPNG, respectively. Therefore, the high-resistivity of NiO and nanoporous GaN depleted by the Fermi-level pinning are advantageous and provide a better piezoelectric performance of the NPNG, compared with that of the TPNG.

Flat Optical and Plasmonic Devices Using Area‐Selective Ion‐Beam Doping of Silicon

AbstractHighly doped semiconductors are an emerging platform for plasmonic devices. Unlike in noble metals, the carrier concentration of semiconductors can vary by many orders of magnitude, resulting in a widely tunable range of plasma wavelengths spanning the mid‐infrared and terahertz ranges. In this work, the potential of highly doped, ion‐beam‐patterned silicon is demonstrated as a fabrication‐friendly platform for flat optical devices. Detailed characterization of the optical properties of silicon is performed at various doping levels, and diffractive optical elements and plasmonic frequency‐selective surfaces that operate in the mid‐to‐far‐infrared regime are realized. The resulting optical devices are monolithic, flat, resilient to thermal and physical damage, and can be easily integrated into other silicon‐based platforms.

Carrier accumulation and depletion in point-contact capacitance-voltage measurements

Scanning capacitance microscopy (SCM) is a variation of atomic force microscopy in which a conductive probe tip detects the bias modulated capacitance for the purpose of measuring the nanoscale semiconductor carrier concentration. SCM can be regarded as a point-contact capacitance-voltage system, and its capacitance-voltage properties are different from those of a conventional parallel-plate capacitor. In this study, the charge accumulation and depletion behavior of a semiconductor sample were closely investigated by SCM. By analyzing the tip-sample approach curve, the effective probe tip area and charge depletion depth could be quantitatively determined.

Determination of n-Type Doping Level in Single GaAs Nanowires by Cathodoluminescence.

We present an effective method of determining the doping level in n-type III-V semiconductors at the nanoscale. Low-temperature and room-temperature cathodoluminescence (CL) measurements are carried out on single Si-doped GaAs nanowires. The spectral shift to higher energy (Burstein-Moss shift) and the broadening of luminescence spectra are signatures of increased electron densities. They are compared to the CL spectra of calibrated Si-doped GaAs layers, whose doping levels are determined by Hall measurements. We apply the generalized Planck's law to fit the whole spectra, taking into account the electron occupation in the conduction band, the bandgap narrowing, and band tails. The electron Fermi levels are used to determine the free electron concentrations, and we infer nanowire doping of 6 × 1017 to 1 × 1018 cm-3. These results show that cathodoluminescence provides a robust way to probe carrier concentrations in semiconductors with the possibility of mapping spatial inhomogeneities at the nanoscale.

(Invited) Selection of Channel Layer for the Vertical Oxide TFT

With the development of the virtual reality and augmented reality displays, ultra-high resolution displays become one of the big concerns. People would not be bothered by display pixels when taking closer look at display with the resolution higher than 2000 ppi. The most important factor in the ultra-high resolution display is the pixel area and the smallest TFT size would be the first criteria in the TFT point of view. Although back channel etch (BCE) TFT and self-aligned (SA) TFT have been used for driving high resolution LCD and OLED, respectively, typical planar structured TFT would not permit display with ultra-high resolution. The vertical TFT with the smallest pixel pitch value among the TFT structures is suitable candidate. Furthermore, channel length of the vertical TFT can be precisely controlled by the thin film thickness of spacer. This results in high and uniform on-current of TFT. Meanwhile, vertical TFT can also provide channel length longer than the sub-pixel length. When we have to apply high gate voltage depending on the display mode, TFT with longer channel length within smaller sub-pixel size would be necessary. One of the advantages of oxide TFTs lies in the freedom of selection of architecture, materials, and process depending on the device application. Considering the main issue in the vertical TFT, the step coverage of active layer, oxide TFT seems to be the best selection. Oxide semiconductor and gate insulator used for the oxide TFT can be deposited by means of plasma enhanced atomic layer deposition (PEALD), which provides excellent step coverage of films. One of the issues in vertical oxide TFT is the relatively high off-current depending on the mobility of TFT due to the short channel length. Here, we compare the performance of vertical oxide TFTs with the variation of semiconductor’s carrier density. By virtue of the easiness for the modifying carrier concentration of InOx based semiconductor, we could adjust the mobility of vertical TFT with low off-current. Vertical TFT with InOx shows 1.26 mA at Vg = 5 V and Vds = 2.1 V, S.S of 0.14 V/dec., on/off ratio of 107, and Von of -1.8V. Meanwhile at the same driving condition, IGZO shows on-current of 0.23 mA, S.S of 0.12 V/dec., on/off ratio of 108 and Von of -0.2V. We will discuss the best selection for the channel layer of vertical TFT depending on the display mode and show the optimized TFT performance depending on the carrier concentration of semiconductors.

Importance of quantum correction for the quantitative simulation of photoexcited scanning tunneling spectra of semiconductor surfaces

Photoexcited scanning tunneling spectroscopy is a promising technique for the determination of carrier concentrations, surface photovoltages, and potentials of semiconductors with atomic spatial resolution. However, extraction of the desired quantities requires computation of the electrostatic potential induced by the proximity of the tip and the tunnel current. This calculation is based on an accurate solution of the Poisson as well as the continuity equations for the tip-vacuum-semiconductor system. For this purpose, the carrier current densities are modeled by classical drift and diffusion equations. However, for small tip radii and highly doped materials, the drift and diffusion transport model significantly overestimates a semiconductor's carrier concentration near the surface, making the quantification of physical properties impossible. In this paper, we apply quantum correction to the drift and diffusion model, in order to account for the so-called quantum compressibility, i.e., reduced compressibility of the carrier gas due to the Pauli principle, in the region of the tip-induced band bending. We compare carrier concentrations, potentials, and tunnel currents derived with and without quantum correction for $\mathrm{GaN}(10\overline{1}0)$ and GaAs(110) surfaces to demonstrate its necessity.

2D coherent charge transport in highly orderedconducting polymers doped by solid statediffusion.

Doping is one of the most important methods to control charge carrier concentration in semiconductors. Ideally, the introduction of dopants should not perturb the ordered microstructure of the semiconducting host. In some systems, such as modulation-doped inorganic semiconductors or molecular charge transfer crystals, this can be achieved by spatially separating the dopants from the charge transport pathways. However, in conducting polymers, dopants tend to be randomly distributed within the conjugated polymer, and as a result the transport properties are strongly affected by the resulting structural and electronic disorder. Here, we show that in the highly ordered lamellar microstructure of a regioregular thiophene-based conjugated polymer, a small-molecule p-type dopant can be incorporated by solid state diffusion into the layers of solubilizing side chains without disrupting the conjugated layers. In contrast to more disordered systems, this allows us to observe coherent, free-electron-like charge transport properties, including a nearly ideal Hall effect in a wide temperature range, a positive magnetoconductance due to weak localization and the Pauli paramagnetic spin susceptibility.