Cadmium zinc telluride(Cd

1-y

Zn

y

Te

CZT) is the first choice of material for room temperature X-ray and gamma-ray detectors.The common growth techniques are the conventional vertical Bridgman and the high pressure Bridgman method.CZT's large average atomic number

Z～50

makes photoelectric absorption the dominant interaction below 250 keV

and its high density

5.8 g/cm

3

results in short interaction lengths.CZT's large band gap also results in low leakage current and low noise at room temperature.In this research work

the improved vertical Bridgman crystal growth method is used to grow CZT crystal with a nominal Zn concentration of 15 atomic percent

namely Cd

0.85

Zn

0.15

Te.Through by strictly controlling of the cadmium vapor pressure

the high quality CZTingots were obtained.The characterization by several method of CZT(wafer) resulted in

FTIR transmittance

T

>

60% within spectra range 2.5～20 μm at room temperature

the density of precipitate

<

1×10

4

/cm

2

with the precipitate diameter ≤15 μm

dislocation etch pit density DEPD

<

6×10

4

/cm

2

full width at half-maximum of X-ray rocking curve values FWHM

<

20 arcsec with the Cu Kα1 radiation and Si three-crystal monochromator and 15 mm×15 mm spot size

the electrical resistivity ρ

>

10

10

Ω·cm.The single element planar detector for radiative ray detection fabricated with CZT crystal mentioned above is performed.The size of CZT crystal for detector is 5 mm×5 mm×2.5 mm.On both sides of 5 mm×5 mm surface

gold and gold/platinum were evaporated as electrodes.The energy spectra to standard radiation source

125

I and

241

Am were performed by CZT planar detector.The applied bias voltage for CZTplanar detector is 200 V.The characteristic γ-radiation peak of

125

I at 27.5 keV with intensity 74.5% is detected and the characteristic γ-radiation peak of

125

I at 27.2 keV with intensity 39.8% can not be recognized from the energy spectrum for

125

I.The characteristic γ-radiation peak of

241

Am at 59.5 keVis measured with the full width at half-maximum FWHM

<

10%

viz.the resolution is better than

6

keV.In the mean time

the characteristic X-ray escape mixing peaks of tellurium and cadmium located at 34 keV is detected and two characteristic X-radiation peaks of Te-K

α

1

α

2

at 27 keV and Np-L

β1

at 17.5 keV are also recognized.