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InGaAs/InP single-photon avalanche diodes (SPADs) are nowadays employed in many photon-counting applications in the near-infrared range. Photon detection efficiency (PDE) is one of the most important parameters of these detectors and here we present a model to precisely estimate it at different temperatures. Starting from optical and electrical TCAD simulations, we selected the most suitable models for the complex refractive indexes, ionization coefficients and minority carrier lifetime from the literature, and adjusted them so to include temperature and doping dependences. The good agreement between measured and simulated curves shows that our model is a valid tool to estimate PDE before device fabrication.

We present a comprehensive model to estimate photon detection efficiency (PDE) of InGaAs/InP single photon avalanche diodes (SPADs) through bidimensional simulations, including the temperature dependence of both optical and electrical properties, aimed at assisting the design of enhanced-PDE detectors.

We present an InGaAs/InP single-photon avalanche diode (SPAD) with $10 \mu \mathrm{m}$ -diameter active area, designed for fiber-based quantum applications. Improved design and fabrication lead to low dark count rate (1000 cps at 225 K), 25% photon detection efficiency and 100 ps (FWHM) timing jitter.

We present the design and the experimental characterization of a new InGaAs/InP single-photon avalanche diode (SPAD), with two different diameters: i) a 10 μm device, suitable for optical fiber-based quantum applications; ii) a 25 μm one, more appropriate for free-space applications. Compared to a previous generation, we improved the design of the double zinc diffusion and optimized the layer structure. We achieved low dark count rate, around 1 kcps and 4 kcps at 225 K and 5 V excess bias for 10 μm and 25 μm devices, respectively, and down to few tens of counts per seconds at 175 K for the 10 μm detector. At 5 V excess bias and 225 K temperature, both devices also show a high photon detection efficiency (33% at 1064 nm, 31% at 1310 nm and 25% at 1550 nm for the 10 μm SPAD). Afterpulsing has been measured with a custom readout integrated circuit, achieving very low probability values. Timing jitter is comparable to previous-generation devices.