2D pn junctions driven out-of-equilibrium
Chaves Romero, Ferney Alveiro (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Feijoo, Pedro Carlos (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)
Jiménez Jiménez, David (Universitat Autònoma de Barcelona. Departament d'Enginyeria Electrònica)

Date:	2020
Abstract:	The pn junction is a fundamental electrical component in modern electronics and optoelectronics. Currently, there is a great deal of interest in the two-dimensional (2D) pn junction. Although many experiments have demonstrated the working principle, there is a lack of fundamental understanding of its basic properties and expected performances, in particular when the device is driven out-of-equilibrium. To fill the current gap in understanding, we investigate the electrostatics and electronic transport of 2D lateral pn junctions. To do so we implement a physics-based simulator that self-consistently solves the 2D Poisson's equation coupled to the drift-diffusion and continuity equations. Notably, the simulator takes into account the strong influence of the out-of-plane electric field through the surrounding dielectric, capturing the weak screening of charge carriers. Supported by simulations, we propose a Shockley-like equation for the ideal current-voltage (J-V) characteristics, in full analogy to the bulk junction after defining an effective depletion layer (EDL). We also discuss the impact of recombination-generation processes inside the EDL, which actually produce a significant deviation with respect to the ideal behavior, consistently with experimental data. Moreover, we analyze the capacitances and conductance of the 2D lateral pn junction. Based on its equivalent circuit we investigate its cut-off frequency targeting RF applications. To gain deeper insight into the role played by material dimensionality, we benchmark the performances of single-layer MoS2 (2D) lateral pn junctions against those of the Si (3D) junction. Finally, a practical discussion on the short length 2D junction case together with the expected impact of interface states has been provided. Given the available list of 2D materials, this work opens the door to a wider exploration of material-dependent performances.
Grants:	European Commission 785219 European Commission 881603 Agencia Estatal de Investigación RTI 2018-097876-B-C21
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Published in:	Nanoscale advances, Vol. 2, Issue 8 (June 2020) , p. 3252-3262, ISSN 2516-0230

DOI: 10.1039/d0na00267d
PMID: 36134281

11 p, 967.1 KB

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