Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV22)
Publication date: 20th April 2022
Superconducting Nanowire Single Photon Detectors (SNSPDs) were introduced to the market in 2003 and since then have found a niche in multiple quantum optics applications, due to their outstanding properties such as fast instrument response and high quantum efficiency.1 The high quantum efficiency is especially important for material science applications in the IR-range beyond 1000 nm, where other available single photon detectors have a low sensitivity, high dark noise and slow time response.
We have integrated a SNSPD (Single Quantum) into a standard MicroTime 100 confocal fluorescence lifetime microscope (PicoQuant) in order to compare the performance of different SNSPD designs with a standard IR-PMT for time-resolved photoluminescence (TRPL) measurements and imaging on a CIGS ( Cu(InGa)Se2 ) device.
While one of the used SNSPDs had a classical single mode fiber coupling to guide the light onto the sensor, the other detector used an internal multimode fiber instead2.
We detected a significant increase in photoluminescence sensitivity of both designs compared to a standard IR-PMT, as well as a several times higher sensitivity of the multimode-fiber coupled nanowire compared to the singe-mode fiber one, in spite of comparable photon quantum efficiencies in this wavelength range for the sensor only. The increased sensitivity combined with the lower dark count rate resulted in an increase of the signal-to-noise ratio by more than 2 orders of magnitude compared to the IR-PMT.
The high sensitivity of SNSPDs combined with high temporal resolution (instrument response function of the overall system was below 100 ps) allows to identify and investigate highly quenched micrometer-sized defect sides of the thin-layer CIGS sample even at low illumination levels.