Integrated optoelectronic devices represents a fundamental building block of hardware accelerators for photonics neural networks. Nanophotonic electro-optic modulators and detectors have significant performance advantages in power efficiency, communication bandwidth, and parallelism compared to conventional free-space photonics. Here, we present strategies and experimental validations of novel high-performance nanophotonic opto-electronic devices, involving heterogeneous integration of emerging materials into silicon photonic integrated circuits to exploit new functionality and device-scaling laws for efficient and ultrafast modulators, detectors, and photonic nonvolatile memory. The optoelectronic implementations of neural networks are demonstrated which significantly extends the spectrum of information processing capabilities.