Advanced single-photon detectors in semiconductors and superconductors

Nowadays many applications of various scientific fields (such as physics, biomedicine, electronics, etc.) need to detect very faint and fast light signals, down to the single-photon level. Different kinds of single-photon detectors have been developed in the past, but solid-state detectors have the advantage of high reliability and robustness, thus enabling the development of very compact and portable modulus, while superconductive cryogenic detectors show the best performances achieved for a single-photon detector but within bulky cryostats. The present Ph.D. dissertation is focused on the design, development, characterization and modeling of novel near-infrared single-photon detectors and the associated readout architectures. An extensive characterization of different single-photon detectors is proposed, new structures are presented proving outstanding performance. New physical models are envisioned and validated, guaranteeing new interpretations for phenomena often unclear. Thank to successful international collaboration with other research groups, new detectors and read-out circuits are developed, enabling measurements previously considered unfeasible.

Il presente lavoro di dottorato tratta la progettazione, lo modellizzazione e la caratterizzazione di innovativi rivelatori a singolo fotone nel vicino infrarosso. La caratterizzazione dettagliata di differenti tipologie di rivelatori è presentata, proponendo nuove strutture che hanno dimostrato ottime prestazioni. Nuovi modelli fisici sono stati proposti e dimostrati, al fine di interpretare fenomeni fin ora non chiari. Grazie alle collaborazione con gruppi di ricerca internazionali, nuovi dispositivi e circuiti di read-out sono stati progettati e sviluppati, permettendo nuovi tipologie di analisi e di misure.