Sahu et al. Nanoscale Research Letters 2011, 6:178 http://www.nanoscalereslett.com/content/6/1/178 4. 45 V at a sweep voltage of ± 8 V at an optimum annealing temperature of 1000°C. Frequency-depen- dent C-V and G-V curves show that the charge storage is due to deep traps and minimal contribution from interface traps. Abbreviations NH3: ammonia; C-V: capacitance-voltage; G-V: conductance-voltage; ERDA: elastic recoil detection analysis; ECR-PECVD: electron-cyclotron resonance plasma enhanced chemical vapor deposition; EFTEM: energy-filtered transmission electron microscopy; FTIR, Fourier transform infrared; FWHM: full width at half maxima; HREM, high resolution transmission electron microscopy; MNNOS: metal-nitride-nitride-silicon; MNOS, metal-nitride-oxide- silicon; MONOS: metal-oxide-nitride-oxide-silicon; NVMs: non-volatile charge memories; PL, photoluminescence; QCE: quantum confinement effect; RBS: Rutherford backscattering; SiH4: silane; Si-nps: silicon nanoparticles; SNOS: silicon-nitride-oxide-silicon; SONOS: silicon-oxide-nitride-oxide-silicon; SRSN: silicon-rich a-SiNx:H films; SRSN: silicon-rich silicon nitride. Authors’ contributions BSS and AS designed the study. BSS deposited the samples with the help of FD and GF. BSS investigated and performed all the post-fabrication treatment, carried out all the electrical characterization, FTIR studies, analyzed all the results, and prepared the draft of the manuscript. DM analyzed the RBS and ERDA measurement results. FD and BSS carried out the PL study. MC and FD carried out the TEM studies and investigated the results. Moreover, AS and BSS participated in the coordination of study. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 23 September 2010 Accepted: 28 February 2011 Published: 28 February 2011 References 1. Pavesi L, Lockwood DJ: In Silicon Photonics, Topics in Applied Physics. Volume 94. Berlin: Springer; 2004:1-52. 2. Carreras J, Arbiol J, Garrido B, Bonafos C, Monserrat J: Direct modulation of electroluminescence from silicon nanocrystals beyond radiative recombination rates. Appl Phys Lett 2008, 92:091103. 3. Walters RJ, Bourianoff GI, Atwater HA: Field-effect electroluminescence in silicon nanocrystals. Nat Mater 2005, 4:143. 4. Porti M, Avidano M, Nafria M, Aymerich X, Carreras J, Jambois O, Garrido B: Nanoscale electrical characterization of Si-nc based memory metal- oxide-semiconductor devices. J Appl Phys 2007, 101:064509. 5. Vijaya Prakash G, Cazzanelli M, Gaburro Z, Pavesi L, Iacona F, Franzo G, Priolo F: Nonlinear optical properties of silicon nanocrystals grown by plasma-enhanced chemical vapor deposition. J Appl Phys 2002, 91:4607. 6. Walters RJ, Kik PG, Casperson JD, Atwater HA, Linsdtedt R, Giorgi M, Bourianoff G: Silicon optical nanocrystal memory. Appl Phys Lett 2004, 85:2622. 7. DiMaria DJ, Kirtley JR, Pakulis EJ, Dong DW, Kuan TS, Pesavento FL, Theis TN, Cutro JA, Brorson SD: Electroluminescence studies in silicon dioxide films containing tiny silicon islands. J Appl Phys 1984, 56:401. 8. Gritsenko VA: Structure and Electronic Properties of Amorphous Insulators in Silicon MIS Structures Novosibirsk: Science; 1993, 280. 9. Gritsenko VA, Meerson EE: In Microelectron (Sov). Volume 17. Electron and hole injection from metal in MNOS structures; 1988:249. 10. Gritsenko VA, Meerson EE: On silicon nitride conductivity. Phys Stat Sol A 1980, 62:K131. 11. Molinari M, Rinnert H, Vergnat M: Evolution with the annealing treatments of the photoluminescence mechanism in a-SiNx:H alloys prepared by reactive evaporation. J Appl Phys 2007, 101:123532. 12. Liu C, Li C, Ji A, Ma L, Wang Y, Cao Z: Intense blue photoluminescence from Si-in-SiNx thin film with high-density nanoparticles. Nanotechnology 2005, 16:940. Page 9 of 10 13. Pei Z, Chang YR, Wang HL: White electroluminescence from hydrogenated amorphous-SiNx thin films. Appl Phys Lett 2002, 80:2839. 14. Xu M, Xu S, Chai JW, Long JD, Ee YC: Enhancement of visible photoluminescence in the SiNx films by SiO2 buffer and annealing. Appl Phys Lett 2006, 89:251904. 15. Wegener HAR, Lincoln AJ, Pao HC, O’Connel MR, Oleksiak RE, Lawrence H: The variable threshold transistor, a new electrically-alterable, non- destructiveread-only storage device. Tech Dig IEEE IEDM 1967, 70. 16. Brown WD, Brewer JE, (Eds): Nonvolatile Semiconductor Memory Technology: A Comprehensive Guide to Understanding and Using NVSM Devices New York: IEEE; 1998, (and references therein). 17. Eitan B, Pavan P, Bloom I, Aloni E, Frommer A, Finzi D, NROM: A novel localized trapping, 2-bit nonvolatile memory cell. IEEE Electron Device Lett 2000, 21:543. 18. Mine T, Fujisaki K, Ishida T, Shimamoto Y, Yamada R, Torri K: Electron trap characteristics of silicon-rich silicon nitride thin films. Jpn J Appl Phys 2007, 46:3206. 19. Vamvakas VEm, Gardelis S: FTIR characterization of light emitting Si-rich nitride films prepared by low pressure chemical vapor deposition. Surf Coat Technol 2007, 201:9359. 20. Scardera G, Puzzer T, Conibeer G, Green MA: Fourier transform infrared spectroscopy of annealed silicon-rich silicon nitride thin films. J Appl Phys 2008, 104:104310. 21. Mestanza SNM, Obrador MP, Rodriguez E, Biasotto C, Doi I, Swart JW: Characterization and modeling of antireflective coatings of SiO2, Si3N4, and SiOxNy deposited by electron cyclotron resonance enhanced plasma chemical vapor deposition. J Vac Sci Technol B 2006, 24:823. 22. Xu Q, Ra Y, Bachman M, Li GP: Characterization of low-temperature silicon nitride films produced by inductively coupled plasma chemical vapor deposition. J Vac Sci Technol A 2009, 27:145. 23. Martínez FL, Ruiz-Merino R, del Prado A, San Andrés E, Mártil I, González- Díaz G, Jeynes C, Barradas NP, Wang L, Reehal HS: Bonding structure and hydrogen content in silicon nitride thin films deposited by the electron cyclotron resonance plasma method. Thin Solid Films 2004, 459:203. 24. Rinnert H, Vergnat M, Burneau A: Evidence of light-emitting amorphous silicon clusters confined in a silicon oxide matrix. J Appl Phys 2001, 89:237. 25. Iacona F, Franzo G, Spinella C: Correlation between luminescence and structural properties of Si nanocrystals. J Appl Phys 2000, 87:1295. 26. Scardera G, Puzzer T, Perez-Wurfl I, Conibeer G: The effects of annealing temperature on the photoluminescence from silicon nitridemultilayer structures. J Cryst Growth 2008, 310:3680. 27. Kim BH, Cho CH, Kim TW, Park NM, Sung GY, Park SJ: Photoluminescence of silicon quantum dots in silicon nitride by NH3 and SiH4. Appl Phys Lett 2005, 86:091908. 28. Mercaldo LV, Veneri PD, Esposito E, Massera E, Usatii I, Privato C: PECVD in- situ growth of silicon quantum dots in silicon nitride from silane and nitrogen. Mater Sci Eng B 2009, 159:77. 29. Kang SM, Yoon SG, Kim SW, Yoon DH: Luminescence tuning of amorphous Si Quantum dots prepared by plasma-enhanced chemical vapor deposition. J Nanosci Nanotechnol 2008, 8:2540. 30. Austin IG, Jackson WA, Searle TM, Bhat PK, Gibson RA: Photoluminescence properties of a-SiNx:H alloys. Philos Mag B 1985, 52:271. 31. Jackson WA, Searle TM, Austin IG, Gibson RA: Photoluminescence excitation of a-SiNx:H alloys. J Non-Cryst Solids 1985, 77, 78:909. 32. Giorgis F, Vinegoni C, Pavesi L: Optical absorption and photoluminescence properties of a-Si1-xNx:H films deposited by plasma- enhanced CVD. Phys Rev B 2000, 61:4693. 33. Siebert W, Carius R, Fuhs W, Jahn K: Photoluminescence in a-Si1-xCx:H films. Phys Status Solidi B 1987, 140:311. 34. Tessler LR, Solomon I: Photoluminescence of tetrahedrally coordinated a- Si1-xCx:H. Phys Rev B 1995, 52:10962. 35. Robertson J: Defect and impurity states in silicon nitride. J Appl Phys 1983, 54:4490. 36. Robertson J, Powell MJ: Gap states in silicon nitride. Appl Phys Lett 1984, 44:415. 37. Ko C, Joo J, Han M, Park BY, Sok JH, Park K: Annealing effects on the photoluminescence of amorphous silicon nitride films. J Korean Phys Soc 2006, 48:1277. 38. Mo CM, Zhang L, Xie C, Wang T: Luminescence of nanometer-sized amorphous silicon nitride solids. J Appl Phys 1995, 73:5185.