Spin-polarized photoemission from wurtzite and zinc blende gallium nitride (GaN) photocathodes has been observed and measured. The p-doped GaN photocathodes were epitaxially grown and activated to negative electron affinity with a cesium monolayer deposited on their surfaces. A field-retarding Mott polarimeter was used to measure the spin polarization of electrons photoemitted from the top of the valence band. A spectral scan with a tunable optical parametric amplifier constructed to provide low-bandwidth light revealed peak spin polarizations of 17% and 29% in the wurtzite and zinc blende photocathodes, respectively. Zinc blende GaN results are analyzed with a spin polarization model accounting for experimental parameters used in the measurements, while possible mechanisms influencing the obtained spin polarization values of wurtzite GaN are discussed.

中文翻译：

---

纤锌矿和闪锌矿氮化镓光电阴极自旋偏振光发射的测量


纤锌矿和闪锌矿氮化镓 (GaN) 光电阴极的自旋偏振光发射已被观察和测量。 p 掺杂 GaN 光电阴极是外延生长的，并通过沉积在其表面上的单层铯激活至负电子亲和势。使用场延迟莫特旋光计来测量从价带顶部光发射的电子的自旋极化。使用可调谐光学参量放大器进行光谱扫描以提供低带宽光，结果显示纤锌矿和闪锌矿光电阴极的峰值自旋偏振分别为 17% 和 29%。使用自旋极化模型分析了闪锌矿 GaN 结果，并考虑了测量中使用的实验参数，同时讨论了影响获得的纤锌矿 GaN 自旋极化值的可能机制。