ABSTRACT
In this research, the nanocrystalline porous silicon (PSi) films are prepared by electrochemical
etching of p types silicon wafers with 15 mA/cm2
etching current densities and 15 min etching time
on the formation nanosized pore array. PSi was characterized by the measurement of XRD, FTIR
spectroscopy and atomic force microscopy properties (AFM). We have estimated crystallites size from
X-Ray diffraction about nanoscale for PSi and Atomic Force microscopy confirms the nanometric size
Chemical fictionalization during the electrochemical etching show on the surface chemical
composition of PSi. The atomic force microscopy investigation shows the rough silicon surface. Also,
it is reported the preparation of colloidal CdS nanoparticles NPs prepared by laser ablation in liquid
(LAL) technique by irradiating with a Nd:YAG laser pulses CdS target immersed in methanol and
varying the laser fluence 1.32 J/cm2
. The structural, morphological and optical of CdS NPs has been
studied. XRD measurement disclosed that the CdS NPs were of wurtzite hexagonal crystal structure.
Transmission electron microscopy (TEM) investigation revealed that the synthesized CdS particles are
spherical and have an average particle size in the range of (25 nm). AFM investigations showed that
the produced CdS particles have ball-shape with good disposability. The energy band gap of CdS NPs
prepared with 1.32 J/cm2 laser fluence has been determined from optical properties and found to be in
the range (2.9 eV). Optical constants of CdS NPs were determined from transmittance and reflectance
spectra.The effect of CdS NPs diffusion on properties of PSi Photodetector have reported which
reveals that improving in (Al/PSi/Si/Al). The results show that a linear relationship between 1/C
2 and reverse bias voltage was obtained. The built-in potential have values depending on the etching time
current density and laser flunce. Al/CdSe/PSi/Si/Al photodetector hetrojunction have two peaks of
response located at 415 nm and (700 -800nm) with max sensitivity 0.6 A/W. The maximum
specific detectivity is 6.8 × 1012 𝑐𝑚 · 𝐻𝑧1/2
· 𝑊−1
at 770 nm wavelength
References
[1] Rao C.N.R., Kulkarni G.U., & Thomas P.J., “Nanocrystals: Synthesis, Properties and
Applications” Springer, (2007) 9.
[2] Liz-Marzān L.M., & Kamat P.V., “Nanoscale Materials” Kluwer Academic Publisher,
London, (2003) 5.
[3] Brus L. E. “Electron–electron and electron hole interactions in small semiconductor
crystallites: The size dependence of the lowest excited electronic state” J. Chem. Phys. 80(9)
(1984) 4403.
[4] Dzhafarov T.D., Ongul F., Yuksel S.A., ”Effect of indium diffusion on characteristics of
CdS films and nCdS/pSi heterojunctions”, Vacuum 84(2) (2009) 310.
[5] Powder Diffract. File, JCPDS Internat. Centre Diffract. Data, PA, U.S.A. (2001) 19073-
3273.
[6] Oladeji I.O., Chow L., Ferekides C.S., Viswanathan V., & Zhao Z., “Metal/CdTe/CdS/
Cd1–xZnxS/TCO/glass: a new CdTe thin film solar cell structure”. Sol. Energy Mater. Sol.
Cells, 61(2) (2000) 203.
[7] Brus L.E.,” Quantum crystallites and nonlinear optics” Appl. Phys. A: Mater. Sci. Process,
53 (1991) 465.
[8] Stokes A.R., Wilson A.C.J., Proc Phys Soc, 56 (1944) 174.
[9] Murugan A.V., Kale B.B., Kulkarni A.V., Kunde L.B., & Saaminathan V. “Novel
approach to control CdS morphology by simple microwave-solvothermal method” J. Mater.
Sci.: Materials in Electronics, 16(5) (2005) 295.
[10] Jinxin Z., Gaoling Z., & Gaorong H.,” Preparation of CdS nanoparticles by hydrothermal
method in micro emulsion” Front. Chem. China. 2(1) (2007) 98.
[11] Gong W., Zheng Z., Zheng J., Hu X., & Gao W., ”Water soluble CdS nanoparticles with
controllable size prepared via femtosecond laser ablation”, J. App. Phys. 102(6) (2007)
064304.
[12] Stewart M.P., Buriak J., Chemical and biological applications of porous silicon
technology, Adv. Mater. 12 (2000) 859-869.
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