Large-area avalanche diodes for picosecond time-correlated photon counting

Time-correlated photon counting experiments in life and material sciences demand photodetectors with single photon sensitivity, low noise and high time resolution. We have developed a planar silicon technology that allows the fabrication of large-area single photon avalanche diodes (SPADs) with unprecedented performance. SPAD devices with 100 μm active area diameter are obtained with dark counting rate of 3 kc/s and time resolution of 35 ps at room temperature. The photon detection efficiency peaks at 48% around 530 nm and stays above 30% in all the visible range. After pulsing probability is much lower than 1%. Thanks to the large active area, good optical collection efficiency can be achieved with relatively simple alignment procedures, thus opening the way to the exploitation of these devices in most demanding applications, such as single-molecule spectroscopy.