Figure 7.

UV-vis spectra of the products hydrothermally synthesized in different HCl solutions: a 1 M b 3 M c 5 M d 7 M e 8 M. The inset shows the calculated band-gap energies

Dai et al. Nanoscale Research Letters 2010 5:1829-1835   doi:10.1007/s11671-010-9720-0