California Institute of Technology

Massachusetts Institute of Technology

Matthew D Shaw

Karl Kimon Berggren

Harold Frank Greer

Marco Colangelo

Di Zhu

Boris Korzh

Daniel P Cunnane

Andrew D Beyer

A method for etching a surface including obtaining a structure comprising a plurality of nanowires on or above a substrate and a dielectric layer on or above the nanowires, wherein the dielectric layer comprises protrusions formed by the underlying nanowires; reacting a surface of the dielectric layer with a reactant, comprising a gas or a plasma, to form a reactive layer on the dielectric layer, wherein the reactive layer comprises a chemical compound including the reactant and elements of the dielectric layer and the reactive layer comprises sidewalls defined by the protrusions; and selectively etching the reactive layer, wherein the etching etches the protrusions laterally through the sidewalls so as to planarize the surface and remove or shrink the protrusions.

Methods and systems for atomic layer etching and atomic layer deposition

Conventional readout of a superconducting nanowire single-photon detector (SNSPD) sets an upper bound on the output voltage to be the product of the bias current and the load impedance, I&#xd7;Z, where Zis limited to 50&#x3a9; in standard RF electronics. This limit is broken/exceeded by interfacing the 50&#x3a9; load and the SNSPD using an integrated superconducting transmission line taper. The taper is a transformer that effectively loads the SNSPD with high impedance without latching. The taper increases the amplitude of the detector output while preserving the fast rising edge. Using a taper with a starting width of 500 nm, a 3.6&#xd7; higher pulse amplitude, 3.7&#xd7; faster slew rate, and 25.1 ps smaller timing jitter was observed. The taper also makes the detector's output voltage sensitive to the number of photon-induced hotspots and enables photon number resolution.

Impedance matched superconducting nanowire photodetector for single- and multi-photon detection

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Pasadena, CA, United States of America

Matthew D Shaw