Probing Shallow and Deep Oxygen Traps in Binary Transition Metal Oxide, CoV2O6, Using Ultrafast Pump Probe Spectroscopy
Authors: Anjan Kumar N M, Soumya Mukherjee, Souvick Chakraborty, Ayan Mondal, Debabrata Samanta, Goutam Dev Mukherjee, Venkataramanan Mahalingam, Satyabrata Raj, N. Kamaraju.
Journal: The Journal of Physical Chemistry C (https://pubs.acs.org/doi/epdf/10.1021/acs.jpcc.4c02975)
Transition metal oxides, while promising for optoelectronics, often suffer from performance limitations due to carrier trapping defects. Understanding and mitigating these traps is crucial for enhancing device efficiency.
This study focuses on CoV2O6, a transition metal oxide with unique optical and magnetic properties. Using femtosecond pump-probe spectroscopy, we investigated the ultrafast optical dynamics of CoV2O6 microparticles. Our analysis revealed two distinct types of traps: shallow band-edge states and deeper mid-gap states. These traps were identified through steady-state absorption and photoluminescence measurements, supported by first-principles DFT calculations.
Kinetic modelling of the transient absorption data further confirmed the existence of these traps and their role in capturing photoexcited carriers. We found that shallow traps capture carriers within approximately 2 picoseconds, while deep traps capture them within 30 picoseconds. Our model predicts that approximately 44 % of photoexcited carriers are trapped in shallow traps, and 40 % in deep traps.
This research provides valuable insights into the carrier dynamics and trapping mechanisms in CoV2O6, paving the way for strategies to improve its optoelectronic performance.
The article is now online: https://pubs.acs.org/doi/epdf/10.1021/acs.jpcc.4c02975
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Posted on: September 2nd, 2024