Magnetoconductance anisotropy of a polymer thin film at the onset of metallicity

Abstract

Thin films of poly(2,5-bis(3-dodecyl-2-yl)-thieno[3,2-b]thiophene) (C12-PBTTT) polymer under electrolyte gating and doping are investigated as model systems for organic thin films devices approaching the metallic side of a metal-insulator (M-I) transition. For the most doped samples, with an estimated density reaching 8 × 1020 cm−3 holes and a conductivity exceeding 1000 S cm−1, a positive high-field magnetoconductance is found in a limited temperature range window and only when the field is perpendicular to the sample plane. This signature of weak localization, combined with indications of finite zero-temperature conductivity, allows us to identify delocalized metallic-like transport in these thin films, even though the conductivity decreases when cooling down the samples.

Ionic Glass–Gated 2D Material–Based Phototransistor: MoSe2 over LaF3 as Case Study

“…The performances of our ionic glass photodetector demonstrate the potential of this method to explore novel photoconduction processes and alternative architectures of devices. Our approach is generic, and can be easily extended to any photoconducting nanomaterials, including organic and molecular systems, nanocrystals, and hybrid materials …”

Current crowding issues on nanoscale planar organic transistors for spintronic applications

“…We rely on our recently investigated 20-nm thick PBTTT films that can be highly doped using a polyelectrolyte ad-layer, as previously reported, 24,13 with mobility values reaching 10 cm 2 /Vs. If we consider that the active channel has now a total length of 2 !…”

“…This value ensures the best reproducibility for comparisons between very different channel lengths. See details in references 23 and 24 . Electrodes with sub-µm separation are fabricated by focused ion beam milling or angle evaporation method, 25 with resulting electrodes spaced in the 30-300 nm range (Fig.…”

“…27 Data interpretation therefore requires careful analysis of the possibly anisotropic intrinsic magnetic field dependence of the properties of the material used as active channel. 24 These considerations could be potentially extended to other systems like carbon nanotubes or 2D materials. 28 Even though ballistic charge injection and the significant influence of metallic contacts on 2D materials conductivity make the crowding length possibly different from L T , an exponential-like current variation approximation remains.…”

Non-conventional charge transport in organic semiconductors: magnetoresistance and thermoelectricity

“…10 The magnetoresistance effect is therefore amongst the largest of any nonmagnetic bulk material. OMAR immediately garnered much attention from the scientific community [6][7][8][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] because of its huge potential that could be translated into intriguing technological applications. OMAR devices do not require ferromagnetic electrodes which offers a much higher degree of freedom in the material choice not achievable for other magnetoresistive or conventional organic-based spintronic devices.…”