Observation of site-controlled localized charged excitons in CrI3/WSe2 heterostructures

Abstract

Isolated spins are the focus of intense scientific exploration due to their potential role as qubits for quantum information science. Optical access to single spins, demonstrated in III-V semiconducting quantum dots, has fueled research aimed at realizing quantum networks. More recently, quantum emitters in atomically thin materials such as tungsten diselenide have been demonstrated to host optically addressable single spins by means of electrostatic doping the localized excitons. Electrostatic doping is not the only route to charging localized quantum emitters and another path forward is through band structure engineering using van der Waals heterojunctions. Critical to this second approach is to interface tungsten diselenide with other van der Waals materials with relative band-alignments conducive to the phenomenon of charge transfer. In this work we show that the Type-II band-alignment between tungsten diselenide and chromium triiodide can be exploited to excite localized charged excitons in tungsten diselenide. Leveraging spin-dependent charge transfer in the device, we demonstrate spin selectivity in the preparation of the spin-valley state of localized single holes. Combined with the use of strain-inducing nanopillars to coordinate the spatial location of tungsten diselenide quantum emitters, we uncover the possibility of realizing large-scale deterministic arrays of optically addressable spin-valley holes in a solid state platform.

Site-controlled interlayer coupling in WSe2/2D perovskite heterostructure

“…The blue shift of PL of IXs in WSe 2 /MoSe 2 heterobilayers has also been reported by reducing the gap between the two layers to enhance interlayer coupling, similar to our scenario [29]. It is assumed that monolayer WSe 2 exhibits a tent-like shape around the pillar, as reported in several studies [17,32,37]. Consequently, the gap between WSe 2 and (iso-BA) 2 PbI 4 is shortened on top of the pillar, yielding enhanced interlayer coupling.…”

“…The formation of moiré potential in vdW heterostructures will change the dynamics and transport properties of IXs significantly [14,15]. Alternative to TMD vdW heterostructures, TMDs can also be combined with other layered materials to achieve interlayer coupling [16][17][18][19]. Recently, it has been demonstrated that robust IXs could be observed in TMD/ two-dimensional (2D) perovskite heterojunctions with various material combinations [20].…”

Challenges and opportunities in 2D heterostructures for electronic and optoelectronic devices

“… (C) Spin-logic with nonvolatile magnetic memory ( Khokhriakov et al., 2021 ). (D) Excitions on WSe 2 in heterostructure with a 2D magnet ( Mukherjee et al., 2020 ). Copyright 2020, Springer Nature.…”

“… (D) Excitions on WSe 2 in heterostructure with a 2D magnet ( Mukherjee et al., 2020 ). Copyright 2020, Springer Nature.…”

Intercalation Strategy in 2D Materials for Electronics and Optoelectronics

“…[ 112,183 ] What is more, with the decrease of dimensionality, the dielectric screening effect is reduced dramatically and Coulomb interactions are significantly improved, which increase the binding energy of many‐body complexes and enable stable existence at room temperature, [ 184,185 ] offering a platform to study the excitons. [ 115,186–190 ] In brief, benefitting from the excellent properties, 2D materials are intriguing for next‐generation photonic and optoelectronic devices. In this section, recent progress of intercalation applied to tune the optical and optoelectronic properties is discussed.…”