Dopant‐Induced Giant Photoluminescence of Monolayer MoS₂ by Chemical Vapor Transport

Abstract

Photoluminescence properties of Ti-doped MoS 2 monolayer. a) The PL spectra of Ti-doped and undoped MoS 2 monolayer. Inset shows normalized spectra. b,c) The corresponding integrated PL intensity maps. d) The PL spectra of the pristine and Ti-doped MoS 2 monolayers collected under the excitation of a 532 nm laser after transferred to SiO 2 /Si substrates.

Improving the Luminescence Performance of Monolayer MoS2 by Doping Multiple Metal Elements with CVT Method

“…According to a previous report, the photoluminescence quantum yield (PLQY) enhancement of two different radiation processes can be roughly estimated by the following equation [37][38][39]: Here, τ D and τ P correspond to the average exciton lifetime of doped and undoped monolayer MoS 2 , respectively. Based on the previous work of our research group [7], we substituted τ 2 to calculate the PLQY enhancement instead of the average lifetime. The calculated value of η is approximately 1.67, confirming the previously observed phenomenon of PL enhancement after Hf doping.…”

“…Compared to before doping, the intensity of the PL increased by many times, corresponding to a significant increase in PL intensity. However, due to the large size of rare earth elements, more defects are introduced after doping, resulting in poor crystal quality and lower PL intensity to Ti doping (our research group has previously reported the relevant work [7]). In addition, we also selected Ti [7], Zr as the IVB group element (Figure S3, Supporting Information), and Dy as the rare earth element for the monolayer MoS 2 doping experiments.…”

“…However, due to the large size of rare earth elements, more defects are introduced after doping, resulting in poor crystal quality and lower PL intensity to Ti doping (our research group has previously reported the relevant work [7]). In addition, we also selected Ti [7], Zr as the IVB group element (Figure S3, Supporting Information), and Dy as the rare earth element for the monolayer MoS 2 doping experiments. It was found that the doping of the Zr element resulted in a two-fold decrease in PL performance.…”

“…The profile of the intensity line in Figure 2 c corresponds to the selected area in Figure 2 b, where Hf and Mo atoms are marked. Except for the bright sites of Hf atoms, all points on the Mo atomic sites exhibit similar contrast, indicating that the Mo atomic vacancies were almost not found on the measured surface [ 7 , 34 ]. Another noteworthy phenomenon is that the strength near the Hf atom substituting the Mo atom is different from that near the Mo atom in other regions ( Figure 2 c).…”

“…In order to expand its application circumstances, doping can be used to regulate the performance of TMDC materials. For instance, doping in TMDCs has the potential to modulate their charge carrier concentration, phase, electronic, and optical band structures, as well as their magnetic properties and may give TMDCs new properties and functionalities for various applications [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Moreover, doped MoS 2 structures can be applied in various technologies such as 2D or 3D, including in photodetectors, transistors, thin-film photovoltaic devices, p-n junctions, non-volatile multi-bit data storage memory, ultrasensitive sensors, and photocatalysts [ 11 ].…”