Anomalous thickness dependence of photoluminescence quantum yield in black phosphorous

Naoki Higashitarumizu, Shiekh Zia Uddin, Daniel Weinberg, Nima Sefidmooye Azar, I. K.M. Reaz Rahman, Vivian Wang, Kenneth B. Crozier, Eran Rabani, Ali Javey*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Black phosphorus has emerged as a unique optoelectronic material, exhibiting tunable and high device performance from mid-infrared to visible wavelengths. Understanding the photophysics of this system is of interest to further advance device technologies based on it. Here we report the thickness dependence of the photoluminescence quantum yield at room temperature in black phosphorus while measuring the various radiative and non-radiative recombination rates. As the thickness decreases from bulk to ~4 nm, a drop in the photoluminescence quantum yield is initially observed due to enhanced surface carrier recombination, followed by an unexpectedly sharp increase in photoluminescence quantum yield with further thickness scaling, with an average value of ~30% for monolayers. This trend arises from the free-carrier to excitonic transition in black phosphorus thin films, and differs from the behaviour of conventional semiconductors, where photoluminescence quantum yield monotonically deteriorates with decreasing thickness. Furthermore, we find that the surface carrier recombination velocity of black phosphorus is two orders of magnitude lower than the lowest value reported in the literature for any semiconductor with or without passivation; this is due to the presence of self-terminated surface bonds in black phosphorus.

Original languageEnglish
Pages (from-to)507-513
Number of pages7
JournalNature Nanotechnology
Volume18
Issue number5
DOIs
StatePublished - May 2023

Funding

FundersFunder number
Australian Research Council Centre of Excellence for Transformative Meta-Optical SystemsCE200100010, DP210103428
U.S. Department of EnergyKCPY23
Office of Science
Basic Energy Sciences
Division of Materials Sciences and EngineeringDE-AC02-05-CH11231, KC1201
Japan Society for the Promotion of Science

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