High band gap nanocrystallite embedded amorphous silicon prepared by hotwire chemical vapour deposition

Structural, electrical and optical properties of nanocrystalline silicon thin films deposited by pulsed laser ablation

“…It may be seen that the samples have indirect band transitions as the value of r comes out to be 1.98 (approximately 2). The band gap energy of samples is found to be$ 2.63 eV which is higher than that of bulk silicon (1.12 eV) and may be due to size effect as also reported by several researchers [31][32][33].…”

Influence of helium dilution of silane on microstructure and opto-electrical properties of hydrogenated nanocrystalline silicon (nc-Si:H) thin films deposited by HW-CVD

“…The typical value of the band gap of a-Si:H is between 1.6 and 1.8 eV depending on the process parameters. The widening of the band gap or reason for high band gap of nc-Si:H films has been attributed by various researchers to the quantum confinement [60], presence of nanocrystallites [61] improvement of short and medium range order [62], presence of oxygen [63] and also to low density amorphous tissues and micro-voids in the film [27]. We think that the high band gap in nc-Si:H thin films observed in the present case may be due to the increase of nanoclusters of nc-Si:H in the amorphous matrix with increase in He dilution of SiH 4 .…”

“…achieving higher deposition rates [26,27]. The method has already been employed for the synthesis of new microcrystalline materials like mc-SiC and mc-GeC for solar cell applications [28].…”

Effect of Silane flow rate on microstructure of Silicon films deposited by HWCVD

“…4a and b) of a-Si, c-Si and silicon in grain boundary region as described in our earlier communication [2] and the references therein. The values of these parameters are listed in Table 1.…”

“…The deposition rate in the case of HWCVD is also found to be higher especially for nano and microcrystalline silicon films, where PECVD requires heavy hydrogen dilution causing the deposition rates to drop down significantly. Interestingly, in HWCVD, the microstructure of the films can be easily changed from amorphous to microcrystalline by just varying any of the process parameter i.e., substrate or filament temperature, process pressure [2,3]. In this paper, we present our results on the influence of pure silane gas flow rate on the microstructure and electrical conductivity of silicon films prepared using HWCVD.…”