Hydrogen plasma induced modification of photoluminescence from a-SiNx:H thin films

Abstract

Articles you may be interested inAccurate determination of optical bandgap and lattice parameters of Zn1-x Mg x O epitaxial films ( 0 ≤ x ≤ 0.3 ) grown by plasma-assisted molecular beam epitaxy on a-plane sapphire A hydrogen storage layer on the surface of silicon nitride films Low temperature (250-350 C) hydrogen plasma annealing (HPA) treatments have been performed on amorphous hydrogenated silicon nitride (a-SiN x :H) thin films having a range of compositions and subsequent modification of photoluminescence (PL) is investigated. The PL spectral shape and peak positions for the as deposited films could be tuned with composition and excitation energies. HPA induced modification of PL of these films is found to depend on the N/Si ratio (x). Upon HPA, the PL spectra show an emergence of a red emission band for x 1, whereas an overall increase of intensity without change in the spectral shape is observed for x > 1. The emission observed in the Si rich films is attributed to nanoscale a-Si:H inclusions. The enhancement is maximum for off-stoichiometric films (x $ 1) and decreases as the compositions of a-Si (x ¼ 0) and a-Si 3 N 4 (x ¼ 1.33) are approached, implying high density of non-radiative defects around x ¼ 1. The diffusion of hydrogen in these films is also analyzed by Elastic Recoil Detection Analysis technique. V C 2014 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4864255] 053525-2Bommali et al.

Annealing and excitation dependent photoluminescence of silicon rich silicon nitride films with silicon quantum dots

“…Among these, Si nanostructures or Si quantum dots (QDs) are one of the best candidates due to their peculiar properties such as quantum confinement effects (QCE) and multiple excitons generation (MEG) [4][5]. Until now, Si QDs dispersed in oxide and nitride matrix have been drastically investigated [6][7][8][9][10][11][12][13][14][15][16][17]. Similar embedded structure has also been reported for other semiconductor QDs [18][19].…”

“…5 tails can be excited. However, pumped by the 532-nm (2.33 eV) laser line, the high energy PL emission from defect levels can't be invoked [12]. In addition, Wu et al…”

Narrow band photocurrent response from partially phase separated a-SiNx:H thin films

“…The PLE monitoring wavelengths were 590 nm and 500 nm as marked against the corresponding curves. both PL spectra 16 and the photocurrent spectral response are excited in mutually exclusive spectral regions.…”

“…The partially phase separated a-SiN x :H shows interesting properties like excitation energy dependent PL 7,15 and a preferential enhancement in PL upon exposure to hydrogen plasma. 16 Further, results presented here become important considering the recent report by Kiriluk et al, 17 which demonstrates the strong absorptive nature and efficient carrier transport in nanocrystalline a-Si:H embedded in amorphous matrices, suggesting the advantage of such materials towards improving solar cell efficiencies.…”

“…In interpreting the results, we continue with the view of Si rich a-SiN x :H, as a composite material as presented in our previous publications. 15,16 …”