The Enhancement of Laser-Induced Transverse Voltage in Tilted Bi2Sr2Co2Oy Thin Films with a Graphite Light Absorption Layer

• 来源期刊: 中国物理快报（英文版）
• 年，卷（期）: 2013,（4）
• 页码范围: 158-160
• 页数: 3页
• 语种: 英文
• DOI: 10.1088/0256-307X/30/4/046801

摘要

Layered cobalt oxides,mainly including MxCoO2 (M=Na,Ca or Sr),Ca3Co4O9 and Bi2Sr2Co2Oy,have attracted great attention as promising thermoelectric materials due to their good thermoelectric performance,low cost and high resistance of oxidation at high temperature in air.[1-3] The crystal structure of these cobalt oxides is composed of two different layers,with an alterative stacking of the conductive CoO2 layer and the insulating Nax (Cax or Srx),Ca2CoO3 or Bi2Sr2O4 layer along the c-axis.This layered structure results in highly anisotropic electronic transport properties with ab-plane Seebeck coefficient Sab being much larger than that of the out-of-plane coefficient Sc.Recently,the laser-induced transverse voltage (LITV) effect has been extensively investigated in the c-axis tilted layered cobalt oxides.[4-9] Detailed studies on the dependence of the induced voltage on the film thickness,the tilted angle as well as the laser irradiation wavelength and direction suggest that the LITV in these layered cobalt oxides mainly originates from the transverse thermoelectric effect.