RESPONSE TIME OF PHOTOEMISSION OF ULTRAFINE PARTICLE THIN FILM

The response time of photoemissive materials is required for detecting ultrashort duration laser pulses. In this paper, the response time of photoemission in ultrafine particle thin film is studied, and the transit time spread (TTS) and response time of peak value (t_M) are discussed. The photoelectron's response time will increase with increasing energy of photons. If the surface potential barrier of thin film declines, the photoemissive sensitivity or quantum yield will rise, however the response time will also increase, which means that response-time characteristic gets worse. As an example, the response time for Ag-O-Cs thin film is calculated for different cases when photoelectrons, excited in Ag ultrafine particles, travel through Cs₂O semiconductor layer to the surface and escape into vacuum. The calculated response time is about 50 fs if this thin film is irradiated by infrared rays of wavelength 1.06μm.     

埋藏于有机介质中金属原子团的结构研究(I)

利用双源同时蒸发和U型管热壁蒸发法制备了两种金属-有机复合薄膜Ag-7,7,8,8-tetracyanoquinodimethane和Ag-1,4-bis-(1,1-dicyanovinyl)-benze.利用透射电子显微镜和可见—紫外光谱研究了所制备的金属-有机复合薄膜的结构特性，发现它们是一种金属原子团埋藏于具有π-共轭体系的有机介质中的薄膜体系. 关键词：     

离子晶体中固溶胶粒的形成和生长以及施主原子浓度(Ⅱ)

本文在前文的基础上进一步讨论了固溶胶粒的生长和施主原子浓度等问题。本文先讨论施主原子浓度的特性,证明它与杂质浓度无关;在胶粒生长后期,施主原子浓度可以近似地用杂质临界浓度表示。施主原子与胶粒的“平衡”,并不意味着系统的自由能处于极小,而是继续缓慢下降,因而在“平衡”条件下测得的施主原子浓度具有一定的零散度。进而从原子扩散角度描述小胶粒缩小和大胶粒生长的物理图象,并讨论了粒子的线度生长速率;接着讨论胶粒有一定分布时的情况。具体讨论了KCl,KBr,KI和NaCl的临界状态,及其有关参量E_β,β。再后就热凝聚和光凝聚等问题进行一些讨论。     

多光子光电发射

光电发射现象,是人们最早观察到的光与固体材料相互作用的基本物理现象之一．１８８７年,赫芝在研究火花放电实验中偶然发现了这一现象．１９０５年,爱因斯坦在总结已有的光电发射实验规律基础上,提出了著名的光的波粒二象性假说,并由此导出了固体材料光电发射公式：其中Ｅｋｍａｘ为发射电子的最大动能,ｈｖ为一个光子的能量,ｈｖｏ为固体材料光电子逸出阈值能量．对金属,ｈｖｏ＝Ｅφ,Ｅφ为材料逸出功;对半导体和?...