Optical properties Violet 4.000A 400nm Indigo 4.250A 425Am Blue 4,700A Visible light:400~700 nm 4700m 4.900Ay 3.1~1.8eV Aqua 4900m 5.500A E=hc/ Green 550pm Yellow 6,000A where c=3X1017 nm/s 600h andh=4.13×10-lseV.s Orange 6,300A 6300M Red 6650A 665nm Dark Red 7,000A 700nm Wavelength(uum) 10%10510410310210110010110210310105103107 Opaque, Translucent-colorful Gamma Ray XRay Ultraviolet Infrared Microwaves Radio Waves Transparent The Visible Spectrum ulttaviolet violet blue green yellow red infrared 400 480 540 580 700 Wavelength (nm]
Optical properties Visible light: 400 ~700 nm 3.1~1.8eV E = hc/l where c = 3×1017 nm/s and h = 4.13×10-15 eV.s Opaque, Translucent –colorful Transparent
Optical properties electronic polarizations *Reflection and transitions of *Absorption electrons Opaque,Eg<1.8eV *Quantized energy of *Transparent, electrons Eg>3.1eV *Photoconductivity *Refraction *Luminescence:short *Internal scattering time,fluorescence; longer time, phosphorescence
Optical properties electronic polarizations and transitions of electrons Quantized energy of electrons Photoconductivity Luminescence: short time, fluorescence; longer time, phosphorescence Reflection Absorption Opaque, Eg<1.8eV Transparent, Eg>3.1eV Refraction Internal scattering
Crystals-atomic level layer A layer B AB packing
layer A layer B AB packing Crystals-atomic level
Unit Cell *smallest structural unit or building block that can describe the crystal structure. 必 Repetition of the unit cell generates the entire crystal. *Different choices of unit cells possible,generally choose parallelepiped unit cell with highest level of symmetry
Unit Cell smallest structural unit or building block that can describe the crystal structure. Repetition of the unit cell generates the entire crystal. Different choices of unit cells possible, generally choose parallelepiped unit cell with highest level of symmetry
Face-Centered Cubic (FCC) *Atoms are located at each of the corners and on the centers of all the faces of cubic unit cell Two representations Cu,Al,Ag,Au of the FCC unit cell
Face-Centered Cubic (FCC) Atoms are located at each of the corners and on the centers of all the faces of cubic unit cell Cu, Al, Ag, Au