1. ALD Thin Film Materials LDRD review 2009NuFact09

2. ALD of III-V semiconductors and other structure/materials What have been done: -GaN -AlN -AlGaN -InN Not too hard for InGaN -TiO 2 -ZnO Other: Pt nanoparticles Ag nanoparticles Cutoff at 380 nm, up to 50% QE at 310 nm BiAlkali’s overlayer for e - emission Absorb at 380nm but surface defect -> re-emits at ~ 540 nm + broad Fill defect on oxide : very high absorption at 380 nm very high absorption above 1000 nm

3. Atomic Layer deposition Home made: -Transfer: Open in air -> issue -No vacuum inside the ALD chamber -Only Thermal ALD Commercial: -Load lock + glove bag: Inert gas (N2, Ar…) for sample transfer -In-situ characterization: Ellipsometry Mass spec QCM and maybe IR spec -In-situ vacuum post annealing -ALD + Plasma ALD

4. Mixed Oxide Deposition: Layer by Layer Mixed Layer Growth Layer by Layer note “steps” atomic layer sequence “digitally” controlled Films Have Tunable Resistivity, Refractive Index, Surface Roughness, etc. [(CH 3 ) 3 Al // H 2 O] 100 nm ZnO Al 2 O 3 [(CH 3 CH 2 ) 2 Zn // H 2 O] Mixed Layers w/ atomic precision Low Temperature Growth Transparent Uniform Even particles in pores can be coated. LDRD review 2009 NuFact09

5. 5 ZnO in Silicon High Aspect Ratio Trench 1 μm 200 nm ZnO Si ALD is very good at coating non-planar surfaces

6. Argonne ALD facilities: Plasma ALD (PEALD) Elemental Metals: Al, Cu, W, Mo… & alloys: NbN, TiN, Pt/Ir etc… Purer materials-> bulk properties -Bi Alkalies: CsI 3 (g) + H 2 (plasma) = CsI + 2HI (g) GeCl 4 (g) + 2H 2 (plasma) = Ge + 4HCl (g). 2SnCl 5 (g) + 10H 2 (plasma) = 2Sn + 10 HCl (g).

7. ITO, conducting-transparent oxides, or Pt, W, Cu, Mo etc.. With plasma ALD Light, λ≤400 nm Work for both Plasma and regular ALD. e-e- Light absorption layer Need Cs layers for QE~50 to 70% d Mean free path e-hole l < d MCP

8. Light, λ≤400 nm e-e- d~50nm, d’~ 10 nm ITO for bias ~ few Volts Metallic wires -> field enhancements: Nanotubes… d’< l MCP Thermal Noise ? -Nanotubes + free space filled with TiO 2 - “AAO” type membrane made out of TiO 2 + ALD filled with metals - AAO membrane filled with both: light absorber and metal Al 2 O 3 Diamond? Metallic layer

9. Shine light laser 325 nm.

10. λ e- AAO e- MCP e- 45 nm Ag nano-particles Al nano-films

11. MCP Metallic electrode absorption e-e- -Cannot use ALD -> coat inside the tube too -Plasma ALD -> lower aspect ratios, controlled by plasma exposure time

12. Light, λ≤400 nm e-e- MCP Light, λ~600 nm Surface plasmon: Gold nanoparticules