均匀掺杂GaAs光阴极表面势垒特性研究

根据激活过程中光电流变化规律及原位光谱响应测试，模拟了GaAs光阴极表面势垒的形成过程，在光阴极表面双偶极子模型的基础上作了修正，建立了三偶极子模型。新模型认为，光阴极表面势垒由三个偶极层套构而成，第一偶极层由GaAs（Zn）-Cs+偶极子组成，第二偶极层由Cs2O偶极子组成，第三偶极层由GaAs-O-Cs偶极子组成，第二、三偶极层嵌入第一偶极层中。根据隧道效应与量子效率测试结果，确立了势垒中分段均匀的电势分布，计算得出势垒宽度为1.65 nm，有效电子亲和势为-0.44 eV。新模型的建立对理解光电阴极表面发射机理具有重要意义。

Characteristic of surface barrier of epuably-doped GaAs photocathode

The photocathode surface barrier formation process of the GaAs photocathode was simulated according to the variation of the photocurrent while the photocathode was activating and in situ tests of spectra response, the two-dipole model was amended to establish a three dipole model. It was considered from the new model that the photocathode surface barrier formed by three kind of dipole layers, the first dipole layer was composed of GaAs(Zn)-Cs+ dipole, the second dipole layer was composed of Cs2O dipole and the third dipole layer was composed of GaAs-O-Cs dipole, the second and third dipole layer embedded in the first dipole layer. The barrier potential distribution which was piecewise uniform was established according to tunnel effect and results of quantum efficiency tests, it was calculated that the width of the barrier is 1.65 nm, and the effective electron affinity energy is -0.44 eV. The establishment of the new model is of great significance to further understand the photocathode surface emission mechanism.