“冷”“热”沉积的Ag-BaO薄膜在红外超短脉冲激光作用下光电发射的比较

Comparision of Photoelectron Emission of Ag-BaO Thin Films Prepared by Cold and Warm Deposition

“冷”、“热”沉积不同制各方式得到Ag－BaO薄膜的光电发射性能显示出不同的特点。在0．53μm超短光脉冲作用下，这两种薄膜的光电发射没有显著差别；在1．06μm超短红外光脉冲作用下的光电发射却表现出较大的差异。实验研究表明：两种制各方式获得的样品在红外超短脉冲激光作用下均为双光子光电发射，但“热沉积”样品比“冷沉积”样品的光电发射量子产额高1个多数量级，前者为5．8×10-7，后者为2．1×10－8。

Deposition conditions may strongly affect photoelectron emission characteristics of Ag-BaO thin films. Two sets of Ag-BaO thin films were grown by warm deposition or by cold deposition. When the films were illuminated by ultra-short laser pulse with a wavelength of 0. 53 pm,no obvious difference ofthe photo-electric emission of the two sets of films was observed. However,if 1. 06μm laser pulse was used in the illumination,significant different electron emission of the two sets of samples was obtained. Our results showed that ultra-short laser pulses produced bi-photon photoelectron emission. The quantum yields of the Ag-BaO films were measured to be 5. 8 ×10-7 for the warm deposition samples and 2. 1×10-8 for the cold deposition samples respectively.