【摘要】 在50~340 K不同温度下,利用紫色激光(λ=405 nm)对银/铋锶钙铜氧2223异质结界面进行辐照,观测到明显的光生电压效应,发现光生电压的极性分别在超导转变温度TC与320 K附近发生了反转,排除了激光产生的热电势是产生光生电压的原因,分析表明银/铋锶钙铜氧2223异质结界面处存在内建电场:光生电压由异质结界面处的内建电场分离光生电子-空穴对产生的。超导转变温度TC之下以及320 K以上,内建电场方向从超导体指向金属电极;超导转变温度TC与反向温度320 K之间,内建电场从金属指向超导体。更多还原

【Abstract】 Photogenerated voltage of Ag/Bi2223 was observed by purple-laser( λ = 405 nm) irradiation range from 50 K to 340 K,it was found that the photogenerated voltage changed in the direction around the superconducting transition temperature TCand 320 K respectively. By analyzing the relationship between the photogenerated voltage effect with the superconducting properties and the heterojunction interface of Ag/Bi2223,it was excluded that the thermoelectric effect induced by laser irradiation is the cause of the photogenerated voltage. We showed that there a built-in electrical field exists the superconductor-normal metal interface, which provided the separation force for the photo-induced electron-hole pairs. The direction of built-in electrical field which below TCand above 320 K points from the superconductor to the metallic electrode. Between TCand 320 K,the interface field points from metal to superconductor.更多还原