Reference : UMR104-ANNLOI-005
Workplace : CHATILLON
Date of publication : Wednesday, June 15, 2022
Type of Contract : FTC Scientist
Contract Period : 12 months
Expected date of employment : 15 July 2022
Proportion of work : Full time
Remuneration : From 2750 to 3900 euros per month according to the candidate experience
Desired level of education : PhD
Experience required : Indifferent
The researcher's mission will be to manufacture by dry process in a glove box Van der Waals heterostructures based on 2D sheets of twisted or untwisted black phosphorus and boron nitride obtained by mechanical exfoliation of bulkcrystals or direct synthesis and to correlate their structural properties and their spectroscopic properties. It will also have the task of defining the continuation of the instrumentalization of the glove box by a spectroscopy diagnosis supplementing the characterization diagnoses already implemented.
The researcher will share his activity on three sites of the consortium of an ANR project (see the context). He will manufacture the heterostructures in an instrumented glove box and their structural characterizations with microscopy and spectroscopy means to which the LEM has access (optics, AFM, TEM, STEM-EELS). Extensive campaigns of Raman spectroscopy and microphotoluminescence in the visible-IR will be carried out in the group of J. Barjon (GEMaC, UVSQ, Versailles). Finally, the passivation of black phosphorus samples as well as transport experiments could be carried out at UMphy-Thalès in the group of P. Sénéor (Palaiseau). This body of experiments will be closely articulated with theoretical work carried out at the LEM on the modeling of quantum effects related to confinement in thin layers and their dielectric environment.
- Good knowledge in semiconductor physics and optical spectroscopy is essential
- experience in the manipulation or study of 2D materials is mandatory as well as and a strong interest for experimentation and technique
- Experience in electron microscopy, digital processing and data analysis (images, datacubes, spectra) will be appreciated.
- Fluent English is expected both orally and in writing, especially for writing scientific articles and reports in the context of collaborative projects.
The project is part of an ANR project piloted by the LEM, which involves the GEMaC laboratories (group of J. Barjon and UMPHY-Thalès (group of P. Sénéor) of the University of Paris Saclay as well as a collaboration with the LP2N (U. Bordeaux, group of E. Gaufrès)). The project is centered on the study of the structural and optoelectronic properties of atomic layers of black phosphorus which entered the family of 2D two-dimensional materials in 2014 and which presents original properties among the semiconductors of this family, due to its crystalline anisotropy and the modulable nature of its electronic gap as a function of the number of atomic layers.
The discovery of two-dimensional materials in 2004 opened up promising prospects in many fields (electronics, mechanics, thermal, spintronics, etc.). Each of these materials has very specific properties that depend on their low dimensionality but also on their own structure and which are the basis of many present and future applications in our daily lives, ranging from flexible screens to nanomedicine. One way to provide additional degrees of freedom over physical effects is to combine, like a lego set, several nanomaterials together. Concretely, it involves manipulating nanomaterials and placing them in interaction in heterostructures to obtain new properties with the promise of further enriching their possibilities. A significant improvement in the performance of atomic layers embedded in heterostructures has already been demonstrated. The optical and electronic properties of these structures remain to be discovered. In particular, in terms of luminescence properties, the richness of the nature of the excitons present in these stacks and at the interface between the layers begins to be revealed (interplane, interface, moiré excitons, etc.) with functionalities promising for optoelectronics (excitronics, twistronics, straintronics).
On the experimental level, the general objective of the project is to design and manufacture different types of heterostructures based on black phosphorus by varying the crystalline orientation between the layers, the number of layers the dielectric of the encapsulating material and to study how these topological characteristics act and condition the opto-electronic properties of the heterostructures thus elaborated.
Constraints and risks
The three laboratories, LEM, GEMaC and UMPHY have proven experience of working together acquired through the conduct of successive projects and the supervision of joint doctoral students and post-doctoral researchers. The means are in place in the various laboratories.
The constraints are the work on several sites and the programming of spectroscopy campaigns at cryogenic temperature.
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