VG Scienta HAXPES analyzers for Academia and Industry

Marcus Lundwall, PhDTechnical Sales Manager, VG Scienta AB

VG Scienta offices and representatives

This talk includes HAXPES results from the following beamlines

with Scienta R4000 10keV spectrometers:

Spring-8/Japan: BL49XU (prof. Kobayashi), BL15 (prof. Ueda), BL29 (prof. Takata)

BESSY II/Germany: HIKE set-up at KMC-1 (Dr. Gorgoi)

Scienta R4000 10keV - Excelling at HAXPES

High resolution HAXPES on Au

Data courtesy: J.J. Kim, K. Kobayashi, Spring-8. SRI 2006 contribution.

HAXPES on Thin Film CIGS Solar Cells: ”Seeing” through the buffer layer

Above approximately 5 Above approximately 5 keVkeV excitation excitation energy the substrate becomes visible! energy the substrate becomes visible!

Depth profiling of Depth profiling of the devicethe device is possible!is possible!

Cu(In,Ga)Se2 (CIGS)Zn(O,S) - 15 nm buffer layer

Glass + Mo

S 1s Zn 2s, 2p

Inte

nsity

/ a.

u.

960eV940920Binding Energy / eV

Cu2p

Data courtesy HIKE (R4000 HE): H. Siegbahn et al., In manuscript.

In this case above 6 keV excitation energy the substrate becomes visible!

ITO (Indium Tin Oxide)Polymer 80-100 nm

Glas s

Sample Structure:

Inte

nsity

/ a.

u.

500 400 300 200 100 0Binding Energy / eV

9000 eV 8000 eV 7000 eV 6000 eV 5000 eV 4000 eV 2000 eV

Inte

nsity

/ a.

u.

480 460 440 420Binding Energy / eV

In 3d

HAXPES on Organic Thin Film Solar Cells

Data courtesy HIKE set-up (R4000 HE), BESSY: W. J. Doherty III, M. Gorgoi, S. Svensson, F. Schaefers, W. Braun, K.-H. Yim, J.-S. Kim, R. H. Friend, W. R. Salaneck, W. Eberhardt. In Manuscript.

HAXPES on Chalcopyrite thin film solar cells Data courtesy: P. Pistor et al., Phys. Status Solidi A 206, 1059 (2009).

Chalcophyrite

thin film solar cells based on Cu(In,Ga)Se2

with an In2

S3

buffer showed high efficiencies above 15%, but only after annealing at 200°C. One possible explanation is a Cu interdiffusion

at the absorber/buffer interface. This has directly been studied using HAXPES at the HIKE endstation

at the BESSY synchrotron.

HAXPES on Chalcopyrite thin film solar cells Data courtesy: P. Pistor et al., Phys. Status Solidi A 206, 1059 (2009).

By heating 2°C/min and recording one Cu 2p spectrum every minute the Cu interdiffusion

within the material was studied. HAXPES gives chemical information through the 20 nm closed In2

S3

overlayer.

VG Scienta MCP/CCD detection system

•

Real-time detector image gives great control over the measurement

Intensity optimisationCheck of sampleLocal charge compensation using flood-gun

•

Fast FireWire connection to the computer

•

Intelligent noise reduction and true pulse counting

•

<0.001 noise counts per channel per second

5 sec

30 sec

∆E=55±5 meV (Ep=50 eV)E/∆E=140000

15min

High Energy Resolution & High Throughput at 7.94 keV

Data courtesy Spring-8 (R4000 HE): Takata et al.

Experimental noise level

A Shirley background is subtracted.

90 89 88 87 86 85 84 83 82 81

Au4f

Inte

nsity

(arb

. uni

t)

Binding Energy (eV)

4f7/24f5

/2

After235 hour

♦BL47XU：

hv =8keV

0 50 100 150 200 25083 .8

83 .9

84 .0

84 .1

84 .2

Au

4f7/

2 pea

k po

sitio

n (B

indi

ng e

nerg

y/eV

)

Time (hour)

Au4f7/2 peak drift

±3meV

0 50 100 150 200 250- 5

- 4

- 3

- 2

- 1

0

1

2

3

4

5

A

u 4f

7/2 P

eak

Are

a D

evia

tion

(%)

Time (hour)

Au4f7/2 peak area

Deviation±1％

Under 300meV Total Resolution

These results indicate that high voltage supply is very stable!

Stability of High Voltage supply

HAXPES on multilayer spintronic structures with x-ray standing waves

Data courtesy: S.-H. Yang, B.C. Sell, and C.S. Fadley, J of Applied Physics 103, 07C519 (2008).

The x-ray standing-wave/wedge method is used for probing the composition, magnetization, and electronic densities of states in buried interfaces and layers in spintronic

nanostructures. It has for example permitted determining concentration and magnetization profiles through giant magnetoresistive

(GMR) and magnetic tunnel junctions structures.

HAXPES on multilayer spintronic structures with x-ray standing waves

Data courtesy: S.-H. Yang, B.C. Sell, and C.S. Fadley, J of Applied Physics 103, 07C519 (2008).

Using the angular mode

of the R4000 10 keV

spectrometer at 6 keV

kinetic energy the hard x-ray standing wave method has been proven to probe deeper into spintronic

multilayers

(C.S. Fadley et al.).

First spectra of Ni 1s core level (EB =8333 eV)

Data courtesy: O. Karis et al., Phys. Rev. B 78, 233105 (2008)

O. Karis

et al. study electron correlations and find that the satellite shift from the Ni 1s is significantly smaller than the well-known 6-eV satellite in Ni 2p. They attribute the energy difference in energy shift to differences in core-valence coupling resulting in different screening of the core holes.

Probing the Electronic Structure of nanoparticle catalysis

Data courtesy: H. Ogasawara, T.Anniyev, L. Å. Näslund, A. Nilsson (SLAC National Accelerator Laboratory). Experiments at Spring-8 BL47XU.

Lab XPS vs. Synchrotron High Energy XPS

1.5 keV 8 keV

λplatinum

= 1.6 nm λplatinum

= 6 nm

Photoionization Cross Section Ratios

0

1

10

100

1000

80eV 800eV 8000eVVUV/soft x-ray PES

Cro

ss S

ectio

n R

atio

[%]

Carbon 2pCopper 3d Platinum 5d

Hard X-ray PES

Surface sensitive bulk sensitive

J.-J. Yeh

and I. Lindau, Data Nucl. Data Tables 32, 1 (1985).

J. H. Scofield, University of California Report No. UCRL 51326, 1973.

Probing the Electronic Structure of nanoparticle catalysis

Data courtesy: H. Ogasawara, T.Anniyev, L. Å. Näslund, A. Nilsson (SLAC National Accelerator Laboratory). Experiments at Spring-8 BL47XU.

Valence band XPS spectra dominated by contributions from support and Cu

With Hard X-ray XPS Pt DOS is now obtainable!

•

PtCu

catalyst shows exceptional Oxygen Reduction Activity (up to 6x times higher than Pt catalyst).

•Core-shell structure determined from XPS.

• Pt shell is compressively strained.

•

Strain induced lowering of the Pt 5d band results in optimized oxygen chemisorption energy.

VG Scienta HAXPES development projects

X-ray source(CrKα）

Objective LensAnalyzer (R4000-10keV)

Wide angle HAXPES

Figure courtesy: K. Kobayashi et al. (NIMS) and H. Diamon et al. (NAIST)

Lens mode: angular; PE=200eV; Slit:S4.0; Beam Size 200um(50W:Crkα); Raster Scan (1mm×1mm)

Total Acceptance angle of 70 degrees

Angle test device (VG SCIENTA)

X-ray Source

-1.0 0.0 1.0Emission Angle (deg)

3208eV

3206

3204

3202

3200

3198

3196

Kin

etic

Ene

rgy

(eV

)

0035 35

- 35 0 35

Inte

nsity

(arb

.uni

ts)

Emission Angle (deg)

Emission angle(deg) Peak width

0 1.13

10 1.17

25 1.11

35 1.53

Angle Resolution Test (Au3d at 3.2 keV)

Data courtesy: K. Kobayashi et al. (NIMS) and H. Diamon et al. (NAIST)

Thank you for your attention!

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