Color centers in diamond are attractive candidates for implementing single-atom quantum memories in a quantum network. This thesis describes an approach to build quantum networks nodes based on color centers in diamond. We propose to use a novel single-atom quantum memory, the neutral charge state of silicon vacancy (SiV0), as the building block for future quantum network. The unique combination of long spin coherence times and efficient optical transitions makes SiV0 a promising candidate for such application. Leveraging the excellent spin and optical properties of SiV0, we design a hybrid III-V diamond photonic platform that can both enhance the photon emission of SiV0 and perform on-chip frequency conversion to the telecommunication C-band. As a first step towards building quantum network nodes based on SiV0, we design, fabricate and characterize nanophotonic cavities on the GaAs-on-diamond platform. Preliminary results show that a quality factor of 1,328 can be achieved despite the challenges in fabrication. Coupling the cavity to a single SiV0 center in diamond could in principle enable a Purcell enhancement of the SiV0 emission with a factor of 64. This could potentially enhance spin readout and spin-photon entanglement fidelity for SiV0. Eventually, the results and techniques described in this thesis could contribute to the developments of multi-node quantum networks that span across the globe.