2D Material Growth and investigation of substrates.
Task 1.1. 2D materials and donor carrier substrates specifications. (M01-M12) [BIU, GRAPHENEA, NTUA, SOUTHAMPTON]
This Task will be led by BIU which in close collaboration with GRAPH, NTUA and SOUTHAMPTON will focus on the identification of the 2D materials carrier concentration and type and the definition of the required Si substrate specifications for constructing light emitting diodes (part of the D2.2, MS1).The doping of silicon will be designed to construct the emitting device as a diode comprised of minority-doped silicon with respect to the majority carrier of the grown semiconductor.
Task 1.2. Growth of Graphene, h-BN and 2D semiconductors. (M01-M30) [BIU, GRAPHENEA]
This Task is dedicated on the development of the growth process of Graphene/h-BN layers and 2D SC (D1.4, MS2). High quality large area monolayer graphene will be grown by GRAPHENEA, on copper foils and metal/dielectric substrates, while for the synthesis of h-BN, various film thicknesses will be synthesised using different metal catalysts such as Cu (thinner films) and Ni (thicker films). BIU will develop detailed processes for the growth of the 2D SCs (Bi2S(3-x)Sex, Sb2Se(3-x)Tex, SnSe(1-x)Tex), and investigate the suitable substrates (e.g. Ge, quartz). A first batch of the grown 2D materials will be delivered to NTUA and ORC during the first year. (D1.1).
Task 1.3. Modelling of optical and electrical properties of the 2D LM. (M01-M30) [NTUA, BIU]
Modelling of materials properties by ab initio calculations will narrow the subspace of materials composition/crystalline structure and will result in concise growth towards desired properties. Using extensive DFT calculations, NTUA will comprehensively study the stability of 2D LM with varying composition (with total energy and phonon calculations), the nature and strength of interfacial interactions and their dependence on monolayer and substrate morphology, the electronic and optical properties of 2D materials (high-level methods will also be employed, e.g. the GW approach or hybrid functionals for the electronic properties and the Bethe-Salpeter method for excitonic effects) and how they are affected by proximal substrates, the possible role of defects, of impurities and of surface passivation. (D1.3)
Task 1.4. Characterization of 2D LM on metallic and metal/dielectric substrates. (M06-M30) [BIU, GRAPHENEA]
Characterization of materials structure, composition and optoelectronic properties will guide the growth efforts with a feedback (D1.2). BIU will also conduct Hall measurements to resolve their carrier concentration and mobilities. The growth parameters (temperature, duration of annealing, the role of growth promoters, relative composition of precursors and choice of substrate), will be tuned according to the characterization results in order to achieve direct bandgaps of 0.7-1.0 eV, so as to converge to an optimal emitter.