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We present photon detection efficiency (PDE) measurements of three different silicon photomultipliers (SiPM) and report the temperature coefficient of this parameter using a direct measurement method. This study provides first results in such a wide temperature and wavelength range, from -30°C to 70°C and from 365 nm to 900 nm respectively. To carry out this study we developed a setup providing stable illumination of the device under test in temperature. The PDE is evaluated using a photon-counting method and the wavelength-dependent PDE temperature coefficients of all devices are determined. The different designs are compared and the individual contributors to the temperature dependence of the PDE are discussed. The PDE is shown to be linearly dependent on temperature for all designs and the temperature coefficient depends on wavelength and bias voltage. At shorter wavelengths, the temperature dependency approaches values close to zero for one design whereas all devices show increasing temperature coefficients for increasing wavelengths. This study shows that despite the more complex designs of SiPMs, compared to silicon photodiodes, similar factors contribute to the temperature dependence of the PDE.

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The Silicon Photomultiplier (SiPM) is a mature photodetector concept that is applied in a variety of applications ranging from medical imaging to automotive LiDAR systems. Over the last few years, improvements of the sensor performance are gradually approaching to a saturation. In this work we present our new concept to overcome the intrinsic limitations of planar configurations of electrodes. Our non-planar technology is based on focusing and enhancing the electric fields by tip-like electrodes. The shape of the electric field and the lack of typical micro-cell edges, allows us to exclude cell separation boundaries and eliminate dead space around active cell areas. Our design provides a high-density micro-cell layout with a high geometric efficiency. It resolves the well-known trade-off between the detection efficiency and the dynamic range. The first "Tip Avalanche Photodiode" (TAPD) prototypes show a remarkable geometric efficiency above 80 % for a micro-cell pitch of 15 µm. This directly translates into a photon detection efficiency (PDE) record peak value of 73 % at 600 nm with respect to the state-of-the-art SiPMs. Moreover, the PDE remains above a value of 45 % up to a wavelength of 800 nm with another record value of 22 % at 905 nm. The reduced micro-cell capacity allows for a fast recovery time below 4 ns, which improves the operation at high photon rates. Overall, the TAPD is anticipated to be a very promising SiPM generation for various wide-spectral and high-dynamic-range applications in health science, biophysics, particle physics and LiDARs.