In molecular beam epitaxy (MBE), nanowires (and shorter “nanorod-like” 1D structures) are grown with atomic-level control, which lets researchers precisely tune composition, crystal phase, doping, and heterostructures—for example axial junctions (p–i–n) and core–shell architectures that are difficult to achieve with solution growth. Because MBE is ultra-high-vacuum and uses controlled elemental fluxes, it can produce high-purity, low-defect nanowires suited for device-grade applications like near-IR photodetectors, avalanche photodiodes, and nanosensors, and it also enables integration strategies on different substrates where strain or lattice mismatch would normally be a problem. In this context, “nanorods” usually refer to shorter 1D segments, but the key MBE advantage remains the same: repeatable growth recipes and engineered interfaces that directly translate into more predictable optical and electronic performance.