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Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
Characterisation of TlBr Crystals for
Detector Applications
V. Kozlov, M. Leskelä and H. Sipilä
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
IWORID2004
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
Detector properties
• Crystal quality
• Purity (composition)
• Previous study* => Chemical aspects• Crystal growth
• Purification
• * V. Kozlov, M. Leskelä, T. Prohaska, G. Schultheis, G. Stingeder and H. Sipilä, Nucl. Instr. and Meth. A (2004) (in press)
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
This study => Crystal quality
• Crystal growth
• Annealing (+hydrothermal)
• Methods:• X-ray rocking curve
• IV & photo-current
• X-ray Cu-radiation
• Polarisation microscope
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
Sample production from the ingot and wafer mapping
• Wafers and, then, slices were cut as is presented in Figure
Sohkl
• Two large crystals of diameter 21 mm were grown using Bridgman method
•<= Reference surface: plane (100) or (111)
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
Rocking curve mapping
1 3 (1 ) m a x -s
M 1 3 ( 1 ) 4 ( 1 ) S e t 2 2
M 1 3 (1 ) 4M 1 3 ( 1 ) 3 ( 3 ) S e t 4 5 M 1 3 ( 1 ) 3 ( 2 ) S e t 4 5 n e w
M 1 3 (1 ) 3M 1 3 ( 1 ) 2 ( 3 ) M 1 3 ( 1 ) 2 ( 1 ) S e t 6 7
M 1 3 (1 ) 2M 1 3 ( 1 ) 1 ( 2 ) s e t 0 0
M 1 3 (1 ) 1
Reference slices =>
All slices were cut || to reference surface
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
Annealing: FWHM change
An03 Src 200oCSL02(111) 0.6 0.6SL05(100) 2.8 1.4SL06(211) ND 0.7
An04 Src 150oC13(1)1(1) 2.5 1.213(1)2(1) 1.3 0.513(2)1(1) 1.8 1.413(2)2(1) 1.2 0.8
Ar atmosphere Pure water
An05 Src 225oC13(1)3(1) 0.7 0.213(1)4(1) 0.65 0.213(2)2(2) 2.7 0.3513(2)3(1) 2.5 0.35
Abr.:ND - not detected13(1)… - (111) planes13(2)… - (100) planes
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
Effects of hydrothermal annealing during 5 days
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
0
200
400
600
800
1000
SourceSet67
13(1) 2(1)2=39.134
Hydrothermal Annealing, 150oC
An04Set55
Inte
nsity
, cn
ts
scan angle
8 9 10 11 12 13 14 15 16 17 18 19 20
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
SourceSet67
13(1) 3(1)2=39.134
Hydrothermal Annealing, 225oC
An05Set67
Inte
nsity
, cn
ts
scan angle
150o C 225o C
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
Source slice10 at a start position
Slice12 annealed at 225o C at a start position
rotation ~-5o
-40o
Effect of TlBr crystal annealing
• Source slice10 and annealed slice12• Sample rotation in Nicole crossed
rotation -42o
rotation ~+15o
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
-250 -200 -150 -100 -50 0 50 100 150 200 250-40.0n
-30.0n
-20.0n
-10.0n
0.0
10.0n
20.0n
30.0n
DarkBox, troom
Emax
= 1kV/cm
SL02mp(111) SL05pm(100) SL06pm(211) SL12pm(ND)
Cur
rent
, nA
Voltage, V
<= Dark box
-250 -200 -150 -100 -50 0 50 100 150 200 250
-400.0n
-300.0n
-200.0n
-100.0n
0.0
100.0n
200.0n
300.0n
400.0n
500.0n
440 nm, troom
Emax
= 1kV/cm
*20
SL02mp 440nm SL02pm 440nm SL02mpdark
Cur
rent
, nA
Voltage, V
Irradiation: 440nm
-200 -100 0 100 200-500.0n
-400.0n
-300.0n
-200.0n
-100.0n
0.0
100.0n
200.0n
300.0n
400.0n
500.0n
SL02mp 440nm SL02pm 440nm SL02mpdark*20
440 nm, troom
Emax
= 1kV/cm
Curr
ent,
nA
Voltage, V
+ “Dark” * 20
IV-measurements
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
-250 -200 -150 -100 -50 0 50 100 150 200 250
-30.0n
-20.0n
-10.0n
0.0
10.0n
20.0n
30.0n
DarkBox, troom
Emax
= 1kV/cm
SL06: Source
Sl06: Ar, 200o C
Cur
rent
, nA
Voltage, V
IV: Annealing
• Annealing: Dry Ar, 200o C
-250 -200 -150 -100 -50 0 50 100 150 200 250-40.0n
-30.0n
-20.0n
-10.0n
0.0
10.0n
20.0n
30.0n
40.0n
50.0n
60.0n
70.0n
80.0n
90.0n
100.0n
110.0n
120.0n
130.0n
140.0n
DarkBox, troom
SL06: Source
Sl06: Ar, 200o C
An04D: water, 150o C
Cur
rent
, nA
Voltage, V
• Annealing: water, 150o C
(unstable characteristic)
-250 -200 -150 -100 -50 0 50 100 150 200 250
-40.0n
-20.0n
0.0
20.0n
40.0n
60.0n
80.0n
100.0n
120.0n
140.0n
160.0n
180.0n
200.0n
DarkBox, troom
SL06: Source
Sl06: Ar, 200o C
An04D: water, 150o C
An05A: water, 225o C
Cur
rent
, nA
Voltage, V
• Annealing: water, 225o C
(unstable characteristic)
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
Photo-Current Spectra
• Non annealed source
• Normalisation by Max200 250 300 350 400 450 500 550 600
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1,0SL02: Source-200 V
Rat
io o
f cu
rren
t: i
/ iM
ax
wavelengh, nm
• Annealing: Ar, 200o C
200 250 300 350 400 450 500 550 600
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1,0SL02: Source
SL02: Ar, 200o C
Rat
io o
f cu
rren
t: i
/ iM
ax
wavelengh, nm
• Annealing: water, 150o C
200 250 300 350 400 450 500 550 600
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1,0SL02: Source
SL02: Ar, 200o C
An04B: water, 150o C
Rat
io o
f cu
rren
t: i
/ iM
ax
wavelengh, nm
• Annealing: water, 225o C
200 250 300 350 400 450 500 550 600
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1,0
SL02: Source
SL02: Ar, 200o C
An04B: water, 150o C
An05C: water, 225o C
Rat
io o
f cu
rren
t: i
/ iM
ax
wavelengh, nm
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
X-ray response
Annealing: Ar, 200o C
0 5 10 15 20 25 30 35 40 45 50-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
E=+-0.5 kV/cmbetween eletrodes
E=+-0.5 kV/cm
E=+-1 kV/cm
Cu-tube, 40 kV
SL02: Ar, 200o C
Det
ecto
r cu
rren
t, A
current, mA
Annealing: water, 150o C
Annealing: water, 225o C
0 5 10 15 20 25 30 35 40 45 50
0
2
4
6
8
10
12
14
E=~-1.5 kV/cm
E=~-1.2 kV/cm
E=+-1 kV/cm
E=~+1.5 kV/cm
E=~+1.2 kV/cm
Cu-tube, 40 kV
SL02: Ar, 200o C
An04D: water, 150o C
An05C: water, 225o C
Det
ecto
r cu
rren
t,
A
current, mA
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
Conclusions
• TlBr grown from melt is stressed and the block boundaries formed have complicated character
• Annealing improves the crystal quality and as result electrical, optical and detection properties
• Annealing in pure water asymmetrically modifies these properties that is probably caused by the concentration gradient of impurities
• Several samples annealed in pure water reveal characteristics of a semiconductor doped
Department of Chemistry, University of Helsinki, Finland METOREX International Oy, Espoo, Finland
Acknowledgements
• Crystal growth: I.S. Lisitsky and M. Kuznetsov (GIREDMET, Russia)
• Electrode deposition Marko Vehkämäki (University of Helsinki)
• European Space Agency ESA
• Finnish Technology Agency TEKES