Arpan De | Searcharxiv

arXiv2026

Charge transfer mediated anomalous photoluminescence enhancement in monolayer MoS2 graphene heterostructure via polystyrene assisted wet transfer

Van der Waals MoS2 graphene heterostructures are compelling candidates for high performance electronic and optoelectronic device applications. However, the interlayer charge transfer typically quenches the photoluminescence of monolayer MoS2, limiting the use of these heterostructures in light emitting applications. In this work, we report an anomalous photoluminescence enhancement in n-type monolayer MoS2 by integrating it with monolayer graphene via polystyrene assisted wet transfer process. Photoluminescence spectroscopy reveals a dominant trion to exciton conversion in the heterostructure. Kelvin probe force microscopy shows a 600 meV increase in the work function of MoS2 upon heterostructure formation. This work function shift, together with the higher work function of graphene, signifies electron transfer from MoS2 to graphene. Shifts in the graphene G and 2D Raman modes further corroborate the interlayer charge transfer. Hydroxyl and epoxy functionalization of graphene following heterostructure formation is evidenced by X ray photoelectron spectroscopy. DFT based Bader charge analysis quantifies the role of these functional groups in facilitating interlayer charge transfer. Collectively, our findings establish polystyrene assisted wet transfer as a practical interface engineering strategy for enhancing excitonic emission in MoS2 graphene heterostructures, thereby advancing their potential for scalable optoelectronic devices.

cond-mat.mes-hall↗

arXiv2023

Performance Analysis of DNA Crossbar Arrays for High-Density Memory Storage Applications

Deoxyribonucleic acid (DNA) has emerged as a promising building block for next-generation ultra-high density storage devices. Although DNA has high durability and extremely high density in nature, its potential as the basis of storage devices is currently hindered by limitations such as expensive and complex fabrication processes and time-consuming read-write operations. In this article, we propose the use of a DNA crossbar array architecture for an electrically readable Read-Only Memory (DNA-ROM). While information can be written error-free to a DNA-ROM array using appropriate sequence encoding, its read accuracy can be affected by several factors such as array size, interconnect resistance, and Fermi energy deviations from HOMO levels of DNA strands employed in the crossbar. We study the impact of array size and interconnect resistance on the bit error rate of a DNA-ROM array through extensive Monte Carlo simulations. We have also analyzed the performance of our proposed DNA crossbar array for an image storage application, as a function of array size and interconnect resistance. While we expect that future advances in bioengineering and materials science will address some of the fabrication challenges associated with DNA crossbar arrays, we believe that the comprehensive body of results we present in this paper establishes the technical viability of DNA crossbar arrays as low-power, high-density storage devices. Finally, our analysis of array performance vis-a-vis interconnect resistance should provide valuable insights into aspects of the fabrication process such as the proper choice of interconnects necessary for ensuring high read accuracies.

cs.ET↗