Axially‐Polarized Excitonic Series and Anisotropic van der Waals Stacked Heterojunction in a Quasi‐1D Layered Transition‐Metal Trichalcogenide

Abstract

Abstract Anisotropic optical 2D materials are crucial for achieving multiple‐quanta functions within quantum materials, which enables the fabrication of axially polarized electronic and optoelectronic devices. In this work, multiple excitonic emissions owning polarization‐sensitive orientations are clearly detected in a multilayered quasi‐1D ZrS3 nanoribbon with respect to the nanostripe edge. Four excitons denoted as AS1, AS2, AS, and A2 with E ⊥ b polarized direction and one prominent A1 exciton with E || b polarized emission are simultaneously detected in the polarized micro‐photoluminescence (µPL) measurement of 1.9–2.2 eV at 10 K. In contrast to light emission, polarized micro‐thermoreflectance (µTR) measurements are performed to identify the polarization dependence and verify the excitons in the multilayered ZrS3 nanoribbon from the perspective of light absorption. At 10 K, a prominent and broadened peak on the lower‐energy side, containing an indirect resonant emission (DI) observed by µPL and an indirect defect‐bound exciton peak (AInd) observed by both µPL and µTR, is simultaneously detected, confirming the existence of a quasi‐direct band edge in ZrS3. A van der Waals stacked p‐GaSe/n‐ZrS3 heterojunction solar cell is fabricated, which demonstrates a maximum axially‐polarized conversion efficiency up to 0.412% as the E || b polarized light incident onto the device.

Keywords

• 2D semiconductor
• excitons
• in‐plane anisotropy
• optical property
• polarized van der waals stacked device