激光辐照引起Ge2Sb2Te5非晶态薄膜的电/光性质变化

研究了激光辐照引起Ge₂Sb₂Te₅非晶态薄膜的电/光性质变化, 当激光功率为580mW时薄膜的方块电阻有四个数量级(10⁷～10³Ω/□)的突变; 对电阻发生突变前、中、后的三个样品进行了XRD测试, 结果表明, 随着激光功率的增大,薄膜由非晶态向晶态转变,用椭偏仪测试了结构转变前、中、后三个样品的光学常数, 在可见光范围内薄膜的光学常数在波长相同情况下有: n_非晶态>n_中间态>n_晶态, k_晶态>k_中间态>k_非晶态, α_晶态>α_中间态>α_非晶态, 结合电阻变化曲线和XRD图谱讨论了激光辐照Ge₂Sb₂Te₅非晶态薄膜的电/光性质变化同激光功率和结构转变之间的关系.

Laser Induced Change in the Electrical and Optical Properties of Amorphous Ge2Sb2Te5 Thin Films

Sheet resistance of laser-irradiated amorphous Ge₂Sb₂Te₅ thin films prepared by magnetron sputtering were measured by the four-point probe method. With the laser power increasing, the sheet resistance undergoes an abrupt change of four orders of magnitude (10⁷-10³Ω/□) at about 580mW. X-ray diffraction studies of the three samples before, at and after the abruption point reveal the phase change process of the Ge₂Sb₂Te₅ thin films from amorphous to crystal states. Optical constants of the three samples measured by ellipsometry have relations as follows, n_amorphous>n_intermediate>n_crystalline, k_crystalline>k_intermediate>k_amorphous, α_crystalline>α_intermediate>α_amorphous. Based on the above results, the relationship between the electrical/optical properties and the structural state of the Ge₂Sb₂Te₅ thin films is discussed.