Growth and optical properties of Sn–Si nanocomposite thin films

Abstract

The growth and optical properties of nanocomposite thin films comprising of nanocrystalline Sn and Si are reported. The nanocomposite films are produced by thermal annealing of bilayers of Sn and Si deposited on borosilicate glass substrates at various temperatures from 300 to 500°C for 1 h in air. X-ray diffraction reveals that the as-deposited bilayers consist of nanocrystalline Sn films with a crystallite size of 30 nm, while the Si thin films are amorphous. There is onset of crystallinity in Si on annealing to 300°C with the appearance of the (111) peak of the diamond cubic structure. The crystallite size of Si increases from 5 to 18 nm, whereas the Sn crystallite size decreases with increase in annealing temperature. Significantly, there is no evidence for any Sn-Si compound, and therefore it is concluded that the films are nanocomposites of Sn and Si. Measured spectral transmittance curves show that the films have high optical absorption in the as-deposited form which decreases on annealing to 300°C. The films show almost 80 % transmission in the visible-near infrared region when the annealing temperature is increased to 500°C. There is concomitant decrease in refractive index from 4.0, at 1750 nm, for the as-deposited film, to 1.88 for the film annealed at 500°C. The optical band gap of the films increases on annealing (from 1.8 to *2.9 eV at 500°C). The Sn-Si nanocomposites have high refractive index, large band gap, and low optical absorption, and can therefore be used in many optical applications.

Tin-induced crystallization of amorphous silicon assisted by a pulsed laser irradiation

“…These experimental results interpreted by the new MIC mechanism proposed in the papers [20][21][22]. It differs significantly from those known for other metals [13,[15][16][17]. According to this mechanism, silicon nanocrystals are formed due to cyclic repetition of formation and decomposition of a supersaturated silicon in tin solution on the narrow eutectic layer at a-Si/Sn interface of tin micro-droplets in amorphous Si volume.…”

“…One of promising ways in this direction is the use of metal-induced crystallization (MIC) of amorphous silicon [13][14][15][16][17]. In particular, the possibility to form Si nanocrystals in amorphous Si matrix at 2 to 5 nm sizes and the phase volume fraction up to 80% was shown by means of tin-stimulated crystallization of amorphous Si at low temperatures [18][19][20].…”

Low temperature Au induced crystallization of titanium dioxide thin films for resistive switching applications

“…The effect of annealing temperature on the crystallization of BT thin lms is presented using X-ray diffraction and Raman spectroscopy in Fig. 20 The calculated crystallite size is approximately same for samples annealed at 400 and 500 C, i.e. The X-ray diffraction pattern of BT thin lms displayed in Fig.…”

“…The XRD pattern of BAT lms annealed at different temperatures have a set of strong diffraction peaks (shown in Fig. 20,26 The Raman spectra of BAT lms annealed at different temperatures presented in Fig. There is a weak diffraction peak at 2q ¼ 30.9 distinctly visible in the magnied XRD pattern in the range of 2q ¼ 28 to 34 in Fig.…”

Tin-Induced Crystallization of Amorphous Silicon under Pulsed Laser Irradiation

“…One of the promising ways in this direction is the application of the phenomenon of metal-induced crystallization (MIC) of amorphous silicon (a-Si) [13][14][15][16][17]. In particular, a possibility to form Si nanocrystals 2-7 nm in dimensions and with a phase volume fraction of up to 80% in the a-Si matrix with the help of the low-temperature tin-induced Si crystallization was demonstrated in [18][19][20].…”