Surface morphology of p-GaAs Seon W. Lee† , H. Hau Wang‡ , Klaus Attenkofer High Energy Physics Division †, Materials Science Division ‡ X-Ray Sciences Division Argonne National Laboratory Tuesday, July 27, 2010 Go to "View | Header and Footer" to add your organization, sponsor, meeting name here; then, click "Apply to All"

Update on Photocathode The active layer exists of 3 layers of GaAs (direct bandgap: 1.456) with different doping: the third layer is 10nm thick with 1x10^18 Zn doping. The thickness of the following layer is varying (0nm,50nm,100nm,200nm) The bottom layer has a 2x10^19 Zn concentration and is 10nm thick Buffer layer Al.75Ga.25As 1um thick layer thick layer (band gap: 2.36eV, IR refractive index 2.95). GaAs substrate (100) Grown by MOVPE (Molecular Vapor Phase Deposition) Sample was grown from (100) GaAs substrate. It grown at UIUC by Ryan. Sample is composed of buffer layer and active layer. Buffer layer is AlGaAs 1um thick. Band gap of buffer layer is 2.36 eV , IR refractive index is 2.95. Active layer is composed of three layer. Grown at UIUC by Ryan Go to "View | Header and Footer" to add your organization, sponsor, meeting name here; then, click "Apply to All"

AFM Image – before annealing 2D Surface Surface roughness : 0.141 nm

After annealing We have some chunks on the surface after annealing samples

After annealing We have some chunks on the surface after annealing samples Surface roughness : rms 0.164nm

Plans in near future EDS (Energy-dispersive X-ray spectroscopy) Analyze chemical composition Surface Cleaning for the elemental analysis or chemical characterization of a sample. EDS spectrum to analyze, analyzing X-rays emitted by the matter in response to being hit with charged particles Go to "View | Header and Footer" to add your organization, sponsor, meeting name here; then, click "Apply to All"