Tunable conduction type of solution-processed germanium nanoparticle based field effect transistors and their inverter integration

Abstract

In this work we demonstrate the fabrication of germanium nanoparticle (NP) based electronics. The whole process chain from the nanoparticle production up to the point of inverter integration is covered. Ge NPs with a mean diameter of 33 nm and a geometric standard deviation of 1.19 are synthesized in the gas phase by thermal decomposition of GeH 4 precursor in a seeded growth process. Dispersions of these particles in ethanol are employed to fabricate thin particulate films (60 to 120 nm in thickness) on substrates with a pre-patterned interdigitated aluminum electrode structure. The effect of temperature treatment, polymethyl methacrylate encapsulation and alumina coating by plasma-assisted atomic layer deposition (employing various temperatures) on the performance of these layers as thin film transistors (TFTs) is investigated. This coating combined with thermal annealing delivers ambipolar TFTs which show an I on /I off ratio in the range of 10 2 . We report fabrication of n-type, p-type or ambipolar Ge NP TFTs at maximum temperatures of 450 1C. For the first time, a circuit using two ambipolar TFTs is demonstrated to function as a NOT gate with an inverter gain of up to 4 which can be operated at room temperature in ambient air.

Morphological and Surface-State Challenges in Ge Nanoparticle Applications

“…Another compelling example of the advantages provided by the use of Ge NP-based composite materials is provided by Meric et al . In this study, the researchers produced a thin film FET based on Ge NPs using a printing technique.…”

“…Another compelling example of the advantages provided by the use of Ge NP-based composite materials is provided by Meric et al 74 In this study, the researchers produced a thin film FET based on Ge NPs using a printing technique. Their work aimed to identify the impact of different encapsulation layers, film morphologies, and post-processing treatments on the Ge NP-based device performance.…”

Bacterial Toxicity of Germanium Nanocrystals Induced by Doping with Boron and Phosphorus

“…Typically, p-type semiconductor nanocrystals are synthesized by doping intrinsic materials with trivalent impurities (such as boron, aluminum, or gallium) during fabrication while n-type semiconductor nanocrystals are created via the incorporation of pentavalent dopants (such as phosphorus, arsenic, or antimony). For semiconductor nanocrystals, the intentional doping plays a critical role in enhancing the materials’ original electrical, optical, , and magnetic properties, leading to a wide range of applications for transistors, , photovoltaics, thermoelectric devices, and light-emitting devices …”

“…Typically, p-type semiconductor nanocrystals are synthesized by doping intrinsic materials with trivalent impurities (such as boron, aluminum, or gallium) during fabrication while n-type semiconductor nanocrystals are created via the incorporation of pentavalent dopants (such as phosphorus, arsenic, or antimony). For semiconductor nanocrystals, the intentional doping plays a critical role in enhancing the materials' original electrical, 33 optical, 34,35 and magnetic 36 properties, leading to a wide range of applications for transistors, 23,37 photovoltaics, 38 thermoelectric devices, 39 and light-emitting devices. 40 However, alongside the incorporation of p-/n-type dopants, redundant holes (h + ) or electrons (e − ) are introduced into the nanoscale network as well, 41 making it possible to generate reactive oxygen species (ROS) via two potential pathways: oxidation of water at the surface of nanocrystals (OH − + h + → • OH) 42 or reduction of molecular oxygen (O 2 + e − → O 2…”

Sulfur-Capped Germanium Nanocrystals: Facile Inorganic Ligand Exchange

“…Inorganic nanocrystals (NCs) represent a potential route to next-generation solar cells, − light-emitting devices, ,− electronics, ,− bioimaging, , and batteries. − The broad interest in these materials results from quantum confinement effects that may be tuned via careful control of the size, shape, composition, and surface characteristics of the nanocrystals. ,,,,− Germanium NCs possess a bulk band gap of 0.67 eV that can be tuned to the near-IR, making them attractive for solar energy conversion and photodetection, − bioimaging, ,, and solid-state lighting. ,− Recent advances in the size-selective synthesis of Ge NCs have shed additional light on the properties and stability of these materials, ,,,,− enabling their use in devices. The original goal in this work was to fabricate a solar cell that employs the attractive characteristics of Ge while circumventing the need for high temperature sintering or sensitivity to air that are caveats exhibited by the CdTe and PbS material systems, respectively. − By using oleylamine-capped Ge NCs followed by a novel ligand exchange process that makes use of elemental S dissolved in alkene, the preparation of thin films that could be implemented in the fabrication of such devices was successfully demonstrated.…”