Effect of Band Symmetry on Photocurrent Production in Quasi-One-Dimensional Transition-Metal Trichalcogenides

Abstract

Photocurrent production in quasi-one-dimensional (1D) transition-metal trichalcogenides, TiS3(001) and ZrS3(001), was examined using polarization-dependent scanning photocurrent microscopy. The photocurrent intensity was the strongest when the excitation source was polarized along the 1D chains with dichroic ratios of 4:1 and 1.2:1 for ZrS3 and TiS3, respectively. This behavior is explained by symmetry selection rules applicable to both valence and conduction band states. Symmetry selection rules are seen to be applicable to the experimental band structure, as is observed in polarization-dependent nanospot angle-resolved photoemission spectroscopy. Based on these band symmetry assignments, it is expected that the dichroic ratios for both materials will be maximized using excitation energies within 1 eV of their band gaps, providing versatile polarization sensitive photodetection across the visible spectrum and into the near-infrared.

Controllable Thermal Oxidation and Photoluminescence Enhancement in Quasi-1D van der Waals ZrS3 Flakes

“…Because ZrS 3 is thought to be an indirect-gap material, with a calculated band gap of ∼1.9 eV, we did not observe a significant PL signal from the as-exfoliated flakes. This is in line with some theoretical predictions that ZrS 3 is an indirect-gap semiconductor, but other factors such as symmetry selection rules may also be significant here, requiring further investigations. ,, …”

“…This is in line with some theoretical predictions that ZrS 3 is an indirect-gap semiconductor, but other factors such as symmetry selection rules may also be significant here, requiring further investigations. 4,24,36 To investigate the thermal stability of ZrS 3 , we treated the exfoliated flakes at an elevated temperature of 350 °C. The evolution of the flakes' optical contrast with treatment time is presented in the panels of Figure 2a.…”

Birefringence and Dichroism in Quasi‐1D Transition Metal Trichalcogenides: Direct Experimental Investigation

“…[ 15 ] The best excitation energy of the dichromatic ratio generated by photocurrent was 1.00–2.0 eV for TiS 3 and 2.0 to 3.0 eV for ZrS 3 . [ 23 ] The optical anisotropies of TiS 3 and ZrS 3 quasi‐1D materials were studied systematically by both theory and experiments, including the optical absorption, reflection, refractive index and extinction coefficient. We studied the reflection and refraction of quasi‐1D TiS 3 and ZrS 3 by using polarization‐resolved optical microscopy (PROM) and azimuth‐dependent reflectance difference microscopy (ADRDM).…”

Anisotropic Properties of Quasi‐1D In4Se3: Mechanical Exfoliation, Electronic Transport, and Polarization‐Dependent Photoresponse

“…[48][49][50][51][52] Strongly polarization-dependent optical properties have been demonstrated for both TiS 3 and ZrS 3 , for linearly polarized light. [53][54][55][56][57][58] This optical photoconductance anisotropy, for the transition metal trichalcogenides, is the result of their quasi-1D crystal structure in which MX 3 (M = Ti, Zr, Hf; X = S, Se, Te) trigonal prisms are formed into 1D chains by strong covalent bonds along the crystallographic b-axis. [42,[53][54][55][56][57]59,60] Similarly, we expected to observe optical photoconductance anisotropy for In 4 Se 3 , which also has a quasi-1D structure (Figure 1a).…”