  Sources of non-classical light are of paramount importance for future
applications in quantum science and technology such as quantum communication,
quantum computation and simulation, quantum sensing and quantum metrology. In
this review we discuss the fundamentals and recent progress in the generation
of single photons, entangled photon pairs and photonic cluster states using
semiconductor quantum dots. Specific fundamentals which are discussed are a
detailed quantum description of light, properties of semiconductor quantum dots
and light-matter interactions. This includes a framework for the dynamic
modelling of non-classical light generation and two-photon interference. Recent
progress will be discussed in the generation of non-classical light for
off-chip applications as well as implementations for scalable on-chip
integration.
