Ultrahigh Room‐Temperature Photoluminescence from Few to Single Quintuple Layer Bi₂Te₃ Nanosheets

Abstract

photoluminescence is considered as one of the primary figures of merit for a 2D semiconductor to be a promising material for nano-optoelectronic, [10,11] sensing, [12,13] and photodetector applications. [14,15] Therefore, it remains challenging to achieve substantial room-temperature photoluminescence response from Bi 2 Te 3 nanocrystals. Additionally, surface plasmon resonance (SPR) defines collective oscillations of conduction electrons and has been attracting highly devoted research interest owing to its promising applications in on-chip subwavelength electro-optical devices, [16][17][18] sensing, [19,20] and energy harvesting. [15,[20][21][22] Due to limited plasmonic materials and modulation methods, effective control over the energy modes and intensities of surface plasmon resonances in the visible region remains challenging.The effective mass approximation (EMA) model describes the opening of bandgaps in ultrathin nanostructures, due to quantum confinement effects. [23] Therefore, dimensionally restricted 2D nanocrystals of Bi 2 Te 3 might provide an opportunity to achieve remarkably enhanced PL properties through the bandgap opening/transition and potentially hold SPR. In recent past, 2D nanocrystals of Bi 2 Te 3 have been reported to support surface plasmons and exhibit PL responses. For instance, visible SPR from 2D Bi 2 Te 3 nanoplates by cathodoluminescence [24] and tunablity of visible SPR modes by Se doping in Bi 2 Te 3 [25] have been demonstrated using PL spectroscopy. Meanwhile, PL spectroscopy, in particular, offers a great opportunity to study quantum confinement-induced exciting phenomena originating from light-matter interactions at the nanoscale. The size-dependent characteristics and physical Owing to its narrow indirect bandgap, bulk bismuth telluride (Bi 2 Te 3 ) exhibits exceptionally low room-temperature photoluminescence (PL). Consequently, it remains challenging to achieve promising optical and optoelectronic performance from Bi 2 Te 3 . Moreover, due to the lack of plasmonic materials and available modulation methods, it is challenging to effectively control the surface plasmon resonance intensities in the visible region. Herein, thickness-dependent photoluminescence studies unveil ultrahigh (282-fold) room-temperature photoluminescence (visible) from 20 quintuple layer Bi 2 Te 3 nanosheets (NSs) compared to 200 quintuple layer NSs, attributable to a significant bandgap opening. Intriguingly, considerable photoluminescence quenching is observed beyond the thickness of 20 quintuple layer Bi 2 Te 3 . The PL emission is further optimized with reference to the number of quintuple layers, and the mechanism possibly responsible for such PL behavior is elucidated. Moreover, the thickness modulation is put forward as an effective strategy to control visible surface plasmon resonance energy modes and their intensities. Bi 2 Te 3 nanosheets with large area and high crystallinity are fabricated on various silicon substrates by a facile hot-pressing strategy, which facilitates investigation of in...

Ultrasensitive broadband photodetectors based on two-dimensional Bi2O2Te films

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Role of Sn Inclusions on Structural, Electrical and Optical Properties of Sb2S3

“…XRD patterns indicate that the increase in tin sulfide leads to the improvement of the film's growth in the favored orientation. For surface morphology and compositional analyses, scanning electron microscopy (SEM) and energydispersive X-ray spectroscopy (EDS) are used [25][26][27][28] . The SEM images of the samples are shown in Figure 3.…”

Topological Materials for Functional Optoelectronic Devices

“…Such tunability has been exemplified by Hussain et al., who reported a thickness‐dependent bandgap and strong and tunable room‐temperature photoluminescence in Bi 2 Te 3 nanosheets. [ 105 ]…”