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Photoconductivity

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Full-Text Articles in Physics

Electrophysical Properties Of Pb 1-Xmnx Se Epitaxial Films Irradiatedby Γ-Quanta, Rahim Madatov, Rakshana Mamishova, Muslim Mamedov, Javanshir Ismayilov, Ulviya Faradjova Jan 2020

Electrophysical Properties Of Pb 1-Xmnx Se Epitaxial Films Irradiatedby Γ-Quanta, Rahim Madatov, Rakshana Mamishova, Muslim Mamedov, Javanshir Ismayilov, Ulviya Faradjova

Turkish Journal of Physics

Herein, the effect of γ-quanta on electrophysical and photoelectric properties of p-type Pb1-xMnx Se epitaxial films obtained from the molecular cluster on the glass substrate by the method of condensation has been investigated. It has been established that the acceptor-type local levels with the ionization energy of 0.14 eV and 0.175 eV are generated, when p-type Pb1-xMnx Se (x = 0.01) epitaxial films are irradiated by γ-quanta at D >10 kGy doses. The increase in the photoconductivity in the low temperature range 80-180K is due to the discharge of 0.14eV level, but the decrease in the rate of change of …


Recombination Mechanisms In Hydrogenated Silicon Nanocrystalline Thin Films, Zaki M. Saleh, Salam M. Kmail, Samah F. Assaf, Atif F. Qasrawi Jan 2013

Recombination Mechanisms In Hydrogenated Silicon Nanocrystalline Thin Films, Zaki M. Saleh, Salam M. Kmail, Samah F. Assaf, Atif F. Qasrawi

Turkish Journal of Physics

The photoconductivity dependences on temperature and illumination intensity were investigated for thin films of hydrogenated nanocrystalline silicon (nc-Si:H) grown by very-high-frequency, plasma-enhanced chemical vapor deposition. The nanocrystalline phase was achieved by heavy hydrogen dilution of silane (SiH_4). We find that the activation energy of the photoconductivity is sensitive to the incident illumination intensity for illumination intensities below 6 mW/cm^2. The photocurrent follows a power-law dependence on illumination intensity (I_{ph}\propto F^{gamma}), with gamma ranging from 0.36 to 0.83. The illumination dependence of the photocurrent suggests 2 different recombination mechanisms depending on temperature. In the lower temperature regime (300-340 K), recombination appears …


Stability Effect In Photoconducting Studies Of Some Chemically Deposited Cds, (Cd-Pb)S And (Cd-Zn)S Films, Shashi Bhushan, Tandesh Chandra Jan 2008

Stability Effect In Photoconducting Studies Of Some Chemically Deposited Cds, (Cd-Pb)S And (Cd-Zn)S Films, Shashi Bhushan, Tandesh Chandra

Turkish Journal of Physics

Stability effects in photoconductivity (PC) rise and decay have been studied over a period of 2 years in thin films of (Cd-Pb)S:LiF, La/Pr and (Cd-Zn)S: LiF,La/Pr and have been found quite stable; however, those of CdS are not that stable. Results of annealing effect are also included, which present more stable values. XRD studies show prominent lines of base materials. Further, XRD and SEM studies show the particle sizes are in the nanometer range. Results of optical absorption spectra have been used to evaluate the band gap of the materials. Effect of thickness of the Ag electrode has also been …


Composition Dependence Of Photoconductivity In Amorphous Thin Films Of Se_{.80-X}Te_{.20}Ge_X, Deepak Kumar, Santosh Kumar Jan 2005

Composition Dependence Of Photoconductivity In Amorphous Thin Films Of Se_{.80-X}Te_{.20}Ge_X, Deepak Kumar, Santosh Kumar

Turkish Journal of Physics

The present paper reports the dependence on composition of photoconductivity in vacuum evaporated thin films of amorphous Se_{.80-x}Te_{.20}Ge_x (x = .05, .10, .15 and .20). Temperature dependence of conductivity in dark as well as in presence of light show that conduction is through a thermally activated process in both cases. The activation energy is found to decrease with increase in light intensity, indicating shift of the Fermi level with intensity. A correlation between activation energy and the pre-exponential factor is observed in all the compositions, which could be fitted to the Meyer-Neldel rule. Measurements on the dependence of photoconductivity on …


Photoconductivity Of Selenium And Sulphur Doped A-Si:H Thin Films, Sanjeev Kumar Sharma, Himanshu Gupta, Rajendra Kumar, Ram Mohan Mehra Jan 2005

Photoconductivity Of Selenium And Sulphur Doped A-Si:H Thin Films, Sanjeev Kumar Sharma, Himanshu Gupta, Rajendra Kumar, Ram Mohan Mehra

Turkish Journal of Physics

This paper presents a study of photoconductivity of S- and Se-doped a-Si:H as a function of composition and temperature. Temperature dependence of photoconductivity of the films was measured under the illumination of white light at 100~mW/cm^2. The room temperature photoconductivity for the same doping concentration of 10^{-4} (to develop H_2Se/SiH_4 and H_2S/SiH_4) is found to be higher in Se-doped -- than S-doped -- a-Si:H film due to a low defect density. From the measurement of intensity dependence of photoconductivity, it is found that the addition of Se and S changes the recombination mechanism from monomolecular, for low-doped films, to bimolecular …


Kinetics Of Light-Induced Metastable Defect Creation And Annealing In A-Si:H, Alp Osman Kodolbaş, Aynur Eray, Özcan Öktü Jan 2002

Kinetics Of Light-Induced Metastable Defect Creation And Annealing In A-Si:H, Alp Osman Kodolbaş, Aynur Eray, Özcan Öktü

Turkish Journal of Physics

Constant Photocurrent Method (CPM) and steady state photoconductivity measurements are used to investigate the creation of light-induced metastable defects in a-Si:H at room temperature and their annealing. Light-induced metastable defect concentration N$_{d}$ varies with exposure time t_{e}as t_{e}^{r} with r=0.34\ pm 0.02, as expected from the recombination induced weak bond breaking model [1]. The validity of a stretched exponential model is also studied [2]. From the annealing experiments, the distribution of thermal annealing activation energies is calculated following the method proposed by Hata and Wagner [3]. Defects created at room temperature show a narrow distribution of annealing activation energies peaking …