We perform a spin polarized density-functional theory (DFT) study of the electronic and magnetic properties of pristine and chemically doped germanene nanoribbons (GeNRs) with different widths. It is found that the Ge atom at the ribbon edge always prefers to be substituted by an impurity atom. Our study reveals that a single N or B atom substitution induces a semiconducting–metal transition in armchair oriented germanene nanoribbons (AGeNRs) as evidenced by the appearance of a half-filled band with less dispersion; however, N and B co-doping at the ribbon edges only modifies their band gaps, due to the accomplishment of an effective charge compensation. A single N or B atom substitution usually turns antiferromagnetic (AFM) semiconducting zigzag germanene nanoribbons (ZGeNRs) into ferromagnetic (FM) semiconductors. This AFM–FM transition is attributed mainly to the perturbation of π and π* states localized at the doped edge. Double atom substitutions (regardless of N–N, B–B or N–B configurations) at the edges of ZGeNRs removes the spin-polarization at both edges and transforms them into non-magnetic (NM) semiconductors. Moreover, it is interesting that some single atom doped ZGeNRs can exhibit a FM half-metallic character with 100% spin-polarization at the Fermi level. Our results suggest that doped AGeNRs and ZGeNRs have potential applications in Ge-based nanoelectronics, such as field effect transistors (FETs), negative differential resistance (NDR) and spin filter (SF) devices.

Nanoparticles below 100 nm have sparked immense interest for their unique physical and chemical properties, separate from bulk materials. These particles have versatile applications in electronics, magnetism, optoelectronics, and electricity. This article overviews ongoing research on nanoparticle-based electronic devices and explores anticipated advancements. In electronics, nanoparticles are essential components for enhanced performance and functionality, promising breakthroughs in computing, telecommunications, and sensing. This work explores the groundbreaking potential of metal-based nanoparticles, such as ZnO NPs, Cu NPs, Al NPs, and Fe NPs, in various electronic device applications. It investigates different synthetic methods, including bottom–up, sol–gel, co-precipitation, hydrothermal, CVD, and green/biological method to enhance the effectiveness of these nanoparticles. The study briefly examines the efficiency of these nanoparticles for electronic device applications, and it extends their potential applications to areas such as data storage, sensors, protective coatings, energy storage, chemical industries, water treatment, fertilizers, and defense. Challenges include precise control of nanoparticle shape and arrangement, which researchers address to design new materials with controlled properties. The present work discusses the anticipated and emerging applications of nanoparticles, emphasizing their unique physical and chemical properties compared to bulk materials. Ongoing research explores their full potential, while manipulation techniques open doors to novel materials. The progress made underscores the immense possibilities of nanoparticle-based electronics.