XRD of InSb films electrodeposited at –1

XRD of InSb films electrodeposited at –1.3 V vs Ag/AgCl, although films were also electrodeposited at other potentials. Figures 1(a), 1(b), and (c) demonstrate the X-ray diffraction pattern of annealed InSb thin films grown at a potential of –1.3 V using three pulse frequencies, 10 Hz 100 Hz, 1 KHz, and 10 KHz, respectively. The XRD patterns reveal sharp intense peaks of InSb demonstrating the good quality of the material grown. The (111) peak, which shows the growth of chalcopyrite phase is present only in some of the patterns (example, Fig. 1(b)), mainly due to the very low structure factor for that plane. The increasing intensity and sharpness of the InSb peaks from (a) to (c) infer that the crystallinity of the electrodeposited samples improves as the pulse frequency increases, and the best crystallinity obtained at a pulse frequency of 10 KHz. This variation in crystallite size with pulse frequency suggests that at lower pulse frequency, the nucleation rate dominates, whereas at higher frequencies, the growth rate is higher than the nucleation rate. Similar dependence of grain size on pulse frequency has been reported by others.2 Figures 2(a), 2(b), and 2(c) show the SEM micrographs and EDAX spectra of annealed InSb films grown using pulses of frequency 10 Hz 100 Hz, 1 KHz, and 10 KHz, respectively at a constant reduction potential of –1.3 V vs Ag/AgCl. It is clearly seen that for the InSb films grown at 1 KHz, the particle size is in the range 50-60 nm (Fig. 2(a)), while for those grown at 100 KHz and 1 MHz it is about 0.6 microns (Fig. 2(b)) and 1 micron (Fig. 2(c), respectively. The EDAX results shown in Fig. 2 indicate that the InSb ratio is close to the stoichiometric ratio of and thus, confirm the good quality of the InSb films grown. It can be seen that there is a slight increase in the In content as the pulse amplitude (deposition potential) increases. These data show there are only minor changes in the composition of the InSb films as the growth parameters such as pulse frequency and pulse