Fabrication and study of multifunctional organic devices integrating spin-crossover compounds

1.     Scientific context 

In the past decade, SCO (spin-crossover) thin films and nanoparticles have been integrated into electronic devices either to investigate the spin-state dependent charge transport properties and/or to obtain new device functionalities¹. Since the SCO leads to a sizeable variation of different physical properties (electronic gap, dielectric permittivity, magnetic moment, etc.), a potentially huge impact of the spin-state switching on the device properties (resistance, capacitance and magnetoresistance) can be predicted. Of particular relevance is the successful fabrication by LCC and LAAS of devices with nanoscale thin films of SCO complexes providing experimental evidence that the spin-state switching leads to a reversible change of the device resistance, with ON/OFF current ratios greater than 100 and good resilience for more than 10.000 endurance cycles^2-4. 

2.     Objectives

In this context, the M2 candidate will focus on the fabrication and characterization of electronic devices involving the most promising SCO compounds synthesized at LCC. Two main types of devices, 2-terminal vertical junctions and lateral 3-terminal devices will be developed to modulate either charge injection or charge transport upon SCO. Different clean-room techniques (photolithography, evaporation, spin-coating…) will be used in order to prepare such devices. Different parameters concerning the films deposition and the devices fabrication (film thickness, device geometry, electrode choice…) will be considered. Device electrical properties will be analyzed as a function of temperature, applied voltage and light irradiation. The set of equipment at LAAS and LCC allows studies of transport properties from 10 to 400 K, including optical excitation at low temperatures. In this perspective, the student will be trained in various deposition techniques (clean room technologies) and device characterization.

3.     Supervision and Collaboration

The internship will take place in the Matériaux et Procédés pour la Nanoélectrique (MPN, I. Séguy) team of the MicroNanoBioTechnologies department of LAAS-CNRS Toulouse (whose research activities are at the intersection of materials engineering, applied physics and life sciences) in close cooperation with the Switchable Molecular Materials team of LCC (G. Molnar and S. Cobo) Toulouse.

4.     Skills and education required 

The Intern candidate is about to earn a Research Master degree or have a university degree equivalent to a European Master’s degree in the area of Physics or Materials Science. An ability to work in a collaborative context at the interface between Physics of Electronic Devices and Materials Science is required. Knowledges or past experiences in Materials science and Electronics are advantageously considered. An attraction for experimentation is also needed.

Applicants should provide a curriculum vitae, a cover letter, a copy of obtained diploma (a certification letter of M1 Degree and anterior diploma) and reference letters from past supervisors or professors. Applications whose curriculum vitae are not in adequacy with the required skills and / or with a cover letter unrelated to the subject will not be considered.

Possibility of pursuing a PhD.

References:

1. Molnár, G., Rat, S., Salmon, L., Nicolazzi, W., & Bousseksou, A. (2018). Spin crossover nanomaterials: from fundamental concepts to devices. Advanced Materials, 30(5), 1703862.
2. Lefter, C., Rat, S., Costa, J. S., Manrique‐Juárez, M. D., Quintero, C. M., Salmon, L., ... & Bousseksou, A. (2016). Current Switching Coupled to Molecular Spin‐States in Large‐Area Junctions. Advanced Materials, 28(34), 7508-7514.
3. Zhang, Y., Séguy, I., Ridier, K., Shalabaeva, V., Piedrahita-Bello, M., Rotaru, A., ... & Bousseksou, A. (2020). Resistance switching in large-area vertical junctions of the molecular spin crossover complex [Fe (HB (tz) 3) 2]: ON/OFF ratios and device stability. Journal of Physics: Condensed Matter, 32(21), 214010.
4. Zhang, Y., Zhang, L., Ridier, K., Salmon, L., Séguy, I., Molnár, G., & Bousseksou, A. (2022). Switching endurance of the molecular spin crossover complex [Fe (HB (tz) 3) 2]: from single crystals to thin films and electronic devices. Materials Advances, 3(22), 8193-8200.