APL Materials · 2014 · 35 citations · 13 references
Natural SciencesMaterials EngineeringMaterials ScienceCrystal StructureMaterials ChemistryOptical MaterialsAmorphous Electronic MaterialsPhotochemistrySemiconductor Crystal GrowthX-ray CrystallographyX-ray DiffractionX-ray OpticsAmorphous-to-crystalline TransformationAmorphous-to-crystalline TransitionsCrystalline StructureIn Situ Phase EvolutionPhotocathodesPhotoresponse CharacterizationQuantum EfficiencySynchrotron X-ray Diffraction
Alkali antimonides have a long history as visible-light-sensitive photocathodes. This work focuses on the process of fabrication of the bi-alkali photocathodes, K2CsSb. In-situ synchrotron x-ray diffraction and photoresponse measurements were used to monitor phase evolution during sequential photocathode growth mode on Si(100) substrates. The amorphous-to-crystalline transition for the initial antimony layer was observed at a film thickness of 40 Å . The antimony crystalline structure dissolved upon potassium deposition, eventually recrystallizing upon further deposition into K-Sb crystalline modifications. This transition, as well as the conversion of potassium antimonide to K2CsSb upon cesium deposition, is correlated with changes in the quantum efficiency.
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