SELENIUM DOPING EFFECT ON THE STRUCTURE AND PROPERTIES OF ZrS2-xSex (x=0, 1, 2)

Thalita Maysha Herninda^1*, Tz-En Peng¹, Ching-Hwa Ho¹

¹Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, Taiwan

* Presenter:Thalita Maysha Herninda, email:talita.maysha@gmail.com

In this work, structure and property of ZrS2 doped with selenium (ZrS2-xSex single crystal with composition x=0, 1, and 2) have been studied. The series layer crystals were grown by CVT method with Iodine as the transport agent. The HRTEM and XRD revealed that ZrS2-xSex (x=0, 1, 2) were crystallized in two-layer hexagonal (2H) structure with the lattice constant decreasing as the selenium composition increased. The energy gap of ZrS2-xSex (x=0, 1, and 2) was shifted to lower energy as the increasing of selenium content. Temperature-dependent Raman of few-layer ZrS2-xSex (x=0, 1, and 2) was also carried out from 4 to 300 K. At 300 K, two Raman vibrational modes (A1g and E1g) were detected and were gradually shifted to lower wavenumber with the increasing of Se. Resistivity and Hall-effect measurement indicated that ZrS2-xSex (x=0, 1, 2) crystals are high conductivity and N-type semiconductors. Carrier concentration and electrical conductivity are simultaneously increased with the increasing of Se content. Thermoelectric measurement of ZrS2-xSex (x=0, 1, 2) was investigated from 25 to 300 K. The ZT of ZrS2-xSex revealed increase with the temperature increased. At 300 K, ZrSe2 demonstrates the highest ZT value of 0.08 among the ZrS2-xSex series layered crystals.

Keywords: Transition Metal Dichalcogenides, 2D Material, Raman, Thermoelectric Properties, ZrS2