Investigations of the tolerance of chalcogenide perovskite semiconductors for point defects
Abstract
Semiconductor device engineering hinges on control of point defects, both desired and undesired. In halide perovskites, control is stymied by factors including- rapid lattice rearrangement at room temperature ( self-healing ), an apparent insensitivity of electrical properties to defects ( defect tolerance ), and an unstable crystal structure that presents difficulties for many characterization methods. We will advance understanding of point defects in perovskite semiconductors by studying chalcogenide perovskites as model systems. Chalcogenide perovskites share salient features with halides, including fast ion diffusion and long excited-state lifetimes. However, unlike the halides, the chalcogenides can be doped both n- and p-type, and their ultra-stable crystal structures permit all manner of experimental studies. We will introduce defects by two methods- doping by ion implantation, and by neutron and gamma ray irradiation. We will study state-of-the-art thin films, leveraging our advances in molecular beam epitaxy. We will identify defects using methods of structural and chemical analysis, including transmission electron microscopy, secondary ion mass spectroscopy, and atom probe tomography. We will characterize the effect of defects on semiconducting properties using measurements of electronic transport, photodetector response, and (time-resolved) photoluminescence spectroscopy. We will measure rates of defect healing under the influence of temperature and illumination. The ability to apply complementary methods, to a model system with excellent structural stability, will enable us to describe the entire lifespan of point defects in perovskite semiconductors, including creation, functionality, and elimination or neutralization by self-healing mechanisms. Our results will update core concepts in semiconductor physics for emerging perovskite materials, and will support the development of technologies based on chalcogenide perovskites.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 14, 2024
- Source ID
- FA95502310695
Entities
People
- Rafael Jaramillo
Organizations
- Air Force Office of Scientific Research
- Massachusetts Institute of Technology
- United States Air Force