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Nanoscale Spectroscopy for Advanced Electronics, Quantum Materials and Devices

Summary

Our goal is to advance nanoelectronic/quantum materials and devices by developing the nanoscale spectroscopic metrology to measure thermal, optical, compositional, and electrical properties quantitatively with nanoscale spatial resolution.

Description

Semiconductor technologies are critical to U.S. economic and national security as they are essential to modern life in communications, healthcare, energy, etc. and also underpin many emerging technologies like quantum, artificial intelligence, high power electronics and advanced wireless (6G+). The next wave of microelectronics innovation will likely stem from the successful integration of heterogeneous materials and
devices through advanced packaging enabling improved yields, functionalities, energy efficiency and cost, at the expense of increased complexity.

Novel, non-destructive, versatile metrology is needed for measuring physical properties (thermal, electrical, optical, …) defects and impurities of new materials (2D, quantum, wide bandgap) and devices with unprecedented spatial and depth resolutions, precision, sensitivity, bandwidth, and throughput is critical to accelerate R&D.

NIST ultrahigh vacuum (UHV) STM
Picture of NIST ultrahigh vacuum (UHV), cryogenic (5K) scanning probe microscope (SPM) platform used for developing atomic-scale resolution spectroscopic techniques such as STM-EL, STM-PL, STM-TERS and PTIR.   

Therefore, this program will advance nanoscale resolution spectroscopic techniques to probe fundamental light-matter and electron-correlation effects at length scales relevant to emerging nanolectronics and quantum devices (typically, 1 to 1000 nm). Such new spectroscopic nanometrology will be leveraged to measure physical properties (e.g., compositional, electrical, thermal, mechanical, optical), transient carrier phenomena (e.g., excitons; polarons; trapping), and their dynamical properties (e.g., free carrier mobilities, heat diffusion) that ultimately affect device performance and efficiencies.

Optomechanical probe PTIR setup
NIST atomic force microscope (AFM) platform uses custom silicon optomechanical resonator probes consisting of a ≈ 100 nm wide cantilever, high optical Q (≈100000) disc resonator (≈ 10 μm diameter) and a waveguide in combination with a wide bandwidth detector. The setup leverages wavelength tunable pulsed laser sources (red) to excite a sample (green) in total internal reflection configuration. In addition to recording the sample topography like a conventional AFM, the high sensitivity of NIST optomechanical probes (≈ 1 fm·Hz-1/2) across a wide bandwidth (≈ 125 MHz) enables measuring the photothermal expansion of the sample with high temporal (≈4 ns) and spatial (≈ 10 nm) resolutions. The amplitude of the photothermal signal is proportional to the absorbed energy in the sample enabling nanoscale chemical imaging and identification by bypassing the diffraction limit of IR spectroscopy. Recording the sample thermal relaxation enable measuring the thermal conductivity and interfacial thermal conductance of the sample at the nanoscale.    

By opening new nanoscale and atomic scale windows for the observation of the complex phenomena mediated by correlated electrons we envision of a broad impact across emerging 2D, nanoscale and quantum materials which may lead to the discovery of new effects and to the engineering of quantum devices.
 

Created December 10, 2010, Updated September 23, 2024