Superconducting nanowire single electron detector
Résumé
WE REPORT THE DETECTION OF SINGLE ELECTRONS USING A 6 NM-THICK, 100 NM-WIDE, NB0.7TI0.3N SUPERCONDUCTING STRIP DEPOSITED ON A SIOX/SI SUBSTRATE. WHEN BIASED SLIGHTLY BELOW THE CRITICAL CURRENT, A MEANDER-SHAPED DEVICE, NOT ONLY DETECTS SINGLE PHOTONS, BUT ALSO COUNTS THE SINGLE KEV ELECTRONS ISSUED FROM A SCANNING ELECTRON MICROSCOPE (SEM) WITH AN EFFICIENCY APPROACHING UNITY. THE RESPONSE TIME IS SHORT ENOUGH TO DISCRIMINATE THE INCIDENT ELECTRONS FROM THOSE BACKSCATTERED FROM THE UNDERLYING MATERIAL. IT IS THEREFORE POSSIBLE TO MAP THE ELECTRON DETECTIVITY AS WELL AS THE PHOTON DETECTIVITY ON THE SAME DEVICE. A CLEAR CORRELATION BETWEEN THE TWO MEASUREMENTS IS OBSERVED, WITH A SUPERIOR SPATIAL RESOLUTION THOUGH (AROUND 100 NM) FOR THE SEM MAPPING. IT ILLUSTRATES THE POTENTIAL USE OF THIS SINGLE ELECTRON MAPPING BY THE SEM METHOD TO CHARACTERIZE THE DETECTION HOMOGENEITY OF SSPDS