Recently integrated optics has become an intriguing platform for implementing machine learning algorithms and in particular neural networks. Integrated photonic circuits can straightforwardly perform vector-matrix multiplications with high efficiency and low power consumption by using weighting mechanism through linear optics. Although, this can not be said for the activation function which requires either nonlinear optics or an electro-optic module with an appropriate dynamic range. Even though all-optical nonlinear optics is potentially faster, its current integration is challenging and is rather inefficient. Here we demonstrate an electro-absorption modulator based on an Indium Tin Oxide layer, whose dynamic range is used as nonlinear activation function of a photonic neuron. The nonlinear activation mechanism is based on a photodiode, which integrates the weighed products, and whose photovoltage drives the elecro-absorption modulator. The synapse and neuron circuit is then constructed to execute a 200-node MNIST classification neural network used for benchmarking the nonlinear activation function and compared with an equivalent electronic module.