Principles and features of single-photon avalanche diode arrays

This is the first of two serial papers dealing on single-photon avalanche diode (SPAD) topics. Aim of the series is to discuss in depth the design and fabrication of our SPAD-A array system for two-dimensional single-photon imaging, able to count and time-tag single photons by means of a monolithic array sensor. This paper deals with the device structure and characterization. The second paper will present the developed fast electronics and will show the overall performance reached in passive, active, and gated regimes. In this first paper we review the working principle and the features of single-photon detector pixels, with particular attention to the monolithic array integration. Then we discuss design criteria, trade-offs, and how to chose operating conditions to attain best performances out of individual pixels. Finally, experimental data will be thoroughly discussed.