X-Ray Radiation Sensing Properties of ZnS Thin Film: A Study on the Effect of Annealing

Sarma, M.P.; Kalita, J.M.; Wary, G.

doi:10.1088/0256-307x/34/7/077802

Cited by 6 publications

(3 citation statements)

References 16 publications

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“…An increase in conductivity could be ascribed to a decrease in the grain boundary as well as the band gap of the material. A similar increase in conductivity with annealing was also observed in the ZnS film [29].…”

Section: Current-voltage (I-v) Characteristicssupporting

confidence: 77%

Influence of annealing on X-ray radiation sensing properties of TiO2 thin film

2017

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A recent study shows that the titanium dioxide (TiO 2 ) thin film synthesised by a chemical bath deposition technique is a very useful material for the X-ray radiation sensor. In this work, we reported the influence of annealing on the X-ray radiation detection sensitivity of the TiO 2 film. The films were annealed at 333 K, 363 K, 393 K, 473 K, and 573 K for 1 hour. Structural analyses showed that the microstrain and dislocation density decreased whereas the average crystallite size increased with annealing. The band gap of the films also decreased from 3.26 eV to 3.10 eV after annealing. The I-V characteristics record under the dark condition and under the X-ray irradiation showed that the conductivity increased with annealing. The influence of annealing on the detection sensitivity was negligible if the bias voltage applied across the films was low (within 0.2 V -1.0 V). At higher bias voltage (>1.0 V), the contribution of electrons excited by X-ray became less significant which affected the detection sensitivity.

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Section: Current-voltage (I-v) Characteristicssupporting

confidence: 77%

Influence of annealing on X-ray radiation sensing properties of TiO2 thin film

2017

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“…In recent times, the use of wide band gap semiconductors for X-ray detection has emerged due to their natural hardness, low dark currents, and ability to sustain high electric fields . Some notable examples of wide band gap materials thst are investigated for X-ray detection are GaN, SiC, β-Ga 2 O 3 , amorphous Ga 2 O 3 (a-Ga 2 O 3 ), ZnO, − TiO 2 , and ZnS. , Among these, the ZnO based sensors have attracted much attention due to its simple method of synthesis, good transparency over the visible light and high radiation hardness. , Several studies on ZnO based X-ray sensors have been reported that encourage its application for flat panel X-ray imaging detectors. However, optimization of its properties for X-ray sensitivity and feasibility of its fabrication to attain the commercial standard are still lacking.…”

Section: Introductionmentioning

confidence: 99%

“…12 Some notable examples of wide band gap materials thst are investigated for X-ray detection are GaN, 13 SiC, 14 β-Ga 2 O 3 , 15 amorphous Ga 2 O 3 (a-Ga 2 O 3 ), 16 ZnO, 17−21 TiO 2 , 22 and ZnS. 23,24 Among these, the ZnO based sensors have attracted much attention due to its simple method of synthesis, good transparency over the visible light and high radiation hardness. 18,20 Several studies on ZnO based X-ray sensors have been reported that encourage its application for flat panel X-ray imaging detectors.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of ZnO Film-Based X-ray Sensors: A Comprehensive Study on the Effect of Thickness of ZnO Layer

Das,

Kalita

2024

ACS Appl. Mater. Interfaces

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For all types of photosensors, efficient absorption of photons of particular interest is very essential. We report the effect of thickness of the ZnO layer in ZnO film-based X-ray sensors. A set of five samples Z1, Z2, Z3, Z4, and Z5 is developed by varying the thickness of the ZnO layer between 10 and 73 μm. The dark I−V characteristics of the sensors show a "pseudorectifying" type nature. A quantitative analysis of the dark currents reveals that the dark I−V characteristics are affected by space charge limited current (SCLC) due to intrinsic defects present in the ZnO films. The effect of the SCLC is prominent in the thicker films in comparison to the thinner ones. The sensors show high signal-tonoise (S/N) ratio below 5.0 V bias voltage. The S/N ratio is found to increase with the thickness of the ZnO layer due to efficient absorption of X-ray photons. The photoresponse characteristics of the sensors against dose rate are sublinear between 0.015 and 0.234 Gy/s. The photoresponse time of the sensors are found to be nearly 1 s. The sensitivities of Z1, Z2, Z3, Z4, and Z5 sensors at 4.5 V bias voltage for 0.234 Gy/s dose rate are estimated to be 55. 51, 337.08, 312.01, 152.81, and 103.52 μC/Gy cm 3 , respectively. The sensitivity of the device is found to increase with increase in thickness of the ZnO layer and reaches an optimum level for the thickness of about 19−26 μm. Beyond this range, the sensitivity is found to decrease due to the Schubweg effect.

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