Alkali-based semiconductor photocathodes are widely used as electron sources and photon detectors. The prop-erties of alkali-based semiconductor materials such as crystallinity and surface roughness fundamentally de-termine the performance merits like quantum efficiency and thermal emittance. In BNL, pulsed laser deposition (PLD) was utilized to assist the growth of alkali-based photocathode materials, providing precise control of material growth and improving film quality. In the pre-sented work, films prepared with thermal and PLD sources are compared. The film quality of K2CsSb, Cs3Sb and Cs2Te grown with PLD assisted technique are reported.

Photocathodes capable of producing spin polarized electrons beams are required for both high energy and nuclear physics experiments. In this work, we describe in detail the commissioning of a new apparatus for photocathode characterization which includes a retarding field Mott polarimeter for the measure of photoelectron spin polarization. We will illustrate the design of superlattice structures equipped with Distributed Bragg Reflector and present the measurements of spin polarization and quantum efficiency of emitted electrons from these structures.