Investigation on the Effect of Crystal Orientation Dependence of Pulse Porous Silicon for White Light Emission

Abstract:

Porous silicon (PS) was formed by using an electrochemical pulse etching (PC) and conventional direct current (DC) etching techniques. The study aims to compare the effect of crystal orientations (n-type (100) and n-type (111)) on the formation of the PS under various conditions. For DC etching technique, the silicon wafers were etched in Hydrofluoric (HF) based solution with a current density of J=10 mA/cm² for 30 minutes. While for the PC process, an electroless chemical etching with a different delay time (T_d) of 0 min and 2 min were imposed before PC process starts. After that, the pulse current of J=10 mA/cm² with the cycle time (T) of 10 ms and pause time (T_off) of 4ms were supplied in 30 min etching time in HF based electrolyte. Three samples from n-type (100) are DC1, PC1 and PC2 while the three samples from n-type (111) are DC2, PC3, and PC4 respectively. Field Emission Scanning Electron Microscopy (FESEM) images showed that the samples from n-type (100) produce more uniform circular structures and dense compared to n-type (111). The introduction of 2 minutes delay during PC process resulted in better structural of PS formation and also the optical properties shown by the Raman and Photoluminescence (PL) spectroscopies. For PL observation, the as grown Si shows no emission at the visible spectrum while all the PS samples (DC and PC techniques) exhibited significant broad spectrum between 500 nm to 900 nm respectively. It can be seen that the uniform circular pore of n-type (100) enhanced the PL emission indicated by the higher PL intensity (PC1 and PC2) compared to PC3 and PC4 from n-type (111). Raman spectroscopy showed that an improvement in the crystalline quality of PS in PC technique compared to DC indicated by the reduction of full width at half maximum (FWHM).

• Periodical: Key Engineering Materials (Volume 701)
• Pages: 164-176
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.701.164
• Online since: July 2016
• Authors: Nurul Hanida Abd Wahab, Alhan Farhanah Abd Rahim*, Fatin Izzanis Mohamad Latar, Ainorkhilah Mahmood
• Keywords: Electrochemical Pulse Etching, Field Emission Scanning Electron Microscopy, Photoluminescence, Porous Silicon, Raman Spectroscopy

References

[1] A. F. Abd Rahim, M. R. Hashim, N. K. Ali, and R. Yusuf, Room temperature Ge and ZnO embedded inside porous silicon using conventional methods for photonic application, Superlattices and Microstructures, 52 (2012) 941-948.

DOI: 10.1016/j.spmi.2012.07.018

[2] S. Chan and P. M. Fauchet, Silicon microcavity light emitting devices, Optical Materials, 17(2001), 31-34.

DOI: 10.1016/s0925-3467(01)00016-7

[3] F. P. Mathew and E. C. Alocilja, Fabrication of porous silicon-based biosensor, Proceedings of 2003 IEEE Sensors, 1 (2003) 293-298.

DOI: 10.1109/icsens.2003.1278945

[4] N. Naderi and M. R. Hashim, Effect of Surface Morphology on electrical Properties of Electrochemically-Etched Porous Silicon Photodetectorss, Int. J. Electrochem. Sci., 7 (2012), 11512-11518.

DOI: 10.1016/s1452-3981(23)16962-8

[5] J. Qi, D. C. Diaz, H. Guan, B. Das, A. Yin, and M. Dobrowolska, Electroluminescence from novel porous silicon p-n junction devices, Proc. SPIE 2150 in Design, Simulation and Fabrication of Optoelectronic Devices and Circuits, 2150 (1994) 96-105.

DOI: 10.1117/12.174980

[6] T. S. T. Amran, M. R. Hashim, N. K. Ali, H. Yazid, and R. Adnan, The role of pulse time Toff on porous silicon as template for Au nanoparticles by using the integrated electrochemical technique, Physica B: Condensed Matter, 407 (2012) 4540-4544.

DOI: 10.1016/j.physb.2012.08.008

[7] N. Naderi, M. R. Hashim, and T. S. T. Amran, Enhanced physical properties of porous silicon for improved hydrogen gas sensing, Superlattices and Microstructures, 51 (2012) 626-634.

DOI: 10.1016/j.spmi.2012.03.010

[8] A. F. Abd Rahim, Studies of Si, Ge and ZnO low dimensional structures synthesized by photoelectrochemical and plasma assisted techniques for sensing applications, Phd thesis, School of Physic, Universiti Sains Malaysia, (2014).

[9] V. Lehmann, B. Jobst, T. Muschik, A. Kux and V. Petrova-Koch, Correlation between optical properties and crystallite size in porous silicon, Applied Physics Letter, 32 (1993), 2095-(2099).

DOI: 10.1143/jjap.32.2095

[10] A. Lorusso, V. Nasisi, G. Congedo, N. Lovergine, L. Velardi and P. Prete, Pulsed plasma ion source to create Si nanocrystals in SiO2 substrates, Applied Surface Science, 255 (2009), 5401-5404.

DOI: 10.1016/j.apsusc.2008.08.030

[11] H. A. Hadi, R. A. Ismail and N. F. Habubi, Fabrication and characterizatiom of porous silicon layer prepared by photo-electrochemical etching in CH3OH: HF solution, International Letters of Chemistry, Physics and Astronomy, 3 (2013) 29-36.

DOI: 10.18052/www.scipress.com/ilcpa.8.29

[12] I. M. Young, M. I. J. Beale and J. D. Benjamin, X-ray double crystal diffraction study of porous silicon, Applied Physics Letter, 46 (1985), 1133-1135.

DOI: 10.1063/1.95733

[13] N. K. Ali, Fabrication and characterization of electrochemically formed nanocrystalline porous Si and GaAs, Phd thesis, Universiti Sains Malaysia, (2008).

[14] H. Diesinger, A. Bsiesy, R. Hérino, and B. Gelloz, Effect of the quantum confinement on the optical absorption of porous silicon, investigated by a new in-situ method, Materials Science and Engineering: B, 69–70 (2000), 167-170.

DOI: 10.1016/s0921-5107(99)00251-2

[15] D. J. Lockwood, A. Wang, and B. Bryskiewicz, Optical absorption evidence for quantum confinement effects in porous silicon, Solid State Communications, 89 (1994), 587-589.

DOI: 10.1016/0038-1098(94)90169-4

[16] N. K. Ali, M. R. Hashim, A. Abdul Aziz, and I. Hamammu, Method of controlling spontaneous emission from porous silicon fabricated using pulsed current etching, Solid-State Electronics, 52 (2008) 249-254.

DOI: 10.1016/j.sse.2007.08.022