Publications / SAND Report

Thermal Infrared Detectors: expanding performance limits using ultrafast electron microscopy

Talin, A.A.; Ellis, Scott R.; Bartelt, Norman C.; Leonard, Francois L.; Perez, Christopher P.; Celio, Km C.; Fuller, Elliot J.; Hughart, David R.; Garland, Diana; Marinella, Matthew J.; Michael, Joseph R.; Chandler, D.W.; Young, Steve M.; Smith, Sean M.; Kumar, Suhas K.

This project aimed to identify the performance-limiting mechanisms in mid- to far infrared (IR) sensors by probing photogenerated free carrier dynamics in model detector materials using scanning ultrafast electron microscopy (SUEM). SUEM is a recently developed method based on using ultrafast electron pulses in combination with optical excitations in a pump- probe configuration to examine charge dynamics with high spatial and temporal resolution and without the need for microfabrication. Five material systems were examined using SUEM in this project: polycrystalline lead zirconium titanate (a pyroelectric), polycrystalline vanadium dioxide (a bolometric material), GaAs (near IR), InAs (mid IR), and Si/SiO 2 system as a prototypical system for interface charge dynamics. The report provides detailed results for the Si/SiO 2 and the lead zirconium titanate systems.