Atomically precise exfoliation of single-crystalline oxide thin-films and its pyroelectric properties
Abstract
Certain single-crystalline complex-oxide materials have shown excellent pyroelectric properties which can offer unique IR remote sensing capability without needing to cool the devices unlike conventional HgCdTe IR detectors. Although it is known that ultrathin pyroelectric films can perform closer to HgCdTe due to the reduced thermal mass and thermal time constant, it has been extremely challenging to produce suspended single-crystalline complex-oxide membranes. This is because of the difficulty in finding a suitable sacrificial layer to release epitaxial complex-oxide films from its substrate. We have recently discovered that a simple mechanical stress produced by depositing a thin Ni stressor layer was sufficient enough to separate, with atomic precision, piezoelectric PMN-PT from its host substrate, SrTiO3 (STO), at the wafer scale. PMN-PT is known for its highest pyroelectric and piezoelectric coefficient and, thus, a perfect candidate to replace HgCdTe IR detectors when they are made into thin-film membrane form. We will investigate the fundamental mechanism which allows for the atomic separation of PMN-PT off of its host substrate, and characterize its pyroelectric properties as a function of the PMN-PT membrane thickness and strain. The main thrust of this project is to (1) establish a fundamental rule in which epitaxial films can be exfoliated off of its host substrate without the need of any sacrificial layer and (2) investigate the physical and mechanical properties of ultrathin freestanding single-crystalline pyroelectric membranes as a function of thickness and strain. Our findings will allow fast and cost efficient creation of ultrathin single-crystalline membranes with superior functional properties such as pyroelectricity, piezoelectricity, and ferroelectricity which are highly desirable for US military applications, as well as for consumer electronics and photonics applications such as sensors, antennas, and quantum computers.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 21, 2022
- Source ID
- FA95502210024XX0
Entities
People
- Jeehwan Kim
Organizations
- Air Force Office of Scientific Research
- Massachusetts Institute of Technology
- United States Air Force