  In this comprehensive study, we undertake a thorough theoretical examination
of the electronic subband structures within cove-edged zigzag graphene
nanoribbons (CZGNRs) using the tight-binding model. These unique nanostructures
arise from the systematic removal of carbon atoms along the zigzag edges of
conventional zigzag graphene nanoribbons (ZGNRs). Notably, CZGNRs that exhibit
intriguing band gaps can be conceptualized as interconnected graphene quantum
dots (GQDs). An essential finding of our investigation is the inverse
relationship between the size of GQDs and the band gaps of CZGNRs, a
relationship that remains consistent regardless of the number of GQDs present.
Additionally, we delve into the examination of electron effective masses in
proximity to the edges of the first conduction subband of CZGNRs as GQD sizes
expand. We observe a significant increase in electron effective masses as GQDs
become larger, which is attributed to the increasing similarity between larger
GQDs and ZGNRs. To further understand the practical implications, we explore
the transport properties of finite CZGNRs when connected to electrodes through
line contacts. The presence of edge defects introduces intriguing asymmetries
in the tunneling current, leading to a significant reduction in its magnitude.
Notably, we observe that the saturation current magnitude is less influenced by
the length of CZGNRs and is instead more sensitive to the choice of materials
used for the contacted electrodes. Lastly, we investigate the tunneling
currents through GQDs featuring boron nitride textures within the Coulomb
blockade region, unveiling an irregular staircase-like pattern in the tunneling
current behavior.
