Recent progress and applications of III–V quantum dots in quantum technologies

III–V quantum dots (QDs) grown by epitaxy are a typical zero-dimensional semiconductor confining electrons and holes with discrete energy levels. Charges, spins, and excitons in QDs can be used to implement qubits for quantum information processing. The radiative recombination of an exciton (electron–hole pair) in a single QD yields coherent single-photon emission. The presence of a resident carrier allows for the deterministic mapping between the stationary spin state and the flying photon polarization, enabling an efficient spin–photon interface. Moreover, QDs can be integrated into on-chip nanophotonic structures, including cavities and waveguides. Owing to these features, III–V QDs have shown great potential for the scalable quantum network. In the past two decades, substantial progress in QD growth techniques, exciton modulation methods, and nanophotonic device fabrication has led to the development of high-performance quantum photonic devices. However, several key challenges still exist, such as the growth of high-quality QDs operating at the telecom band, precise control and enhancement of cavity–QD coupling strength, and deterministic integration of QDs into photonic circuits. This review explores recent progress and applications of III–V QDs, including state-of-the-art growth techniques, advanced exciton control schemes such as resonance fluorescence, investigations of cavity quantum electrodynamics, and single-photon routing through waveguides. In the end, the prospects for realizing a QD-based quantum photonic network for practical applications are also discussed.