Bandgap Engineering in ZnO By Doping with 3d Transition Metal Ions

Abstract

Bulk Zn 0.95 TM 0.05 O (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>TM</mml:mtext><mml:mo>=</mml:mo><mml:mtext>Cr</mml:mtext></mml:math>, Mn, Fe, Co, and Ni) were synthesized by the standard ceramic method and explored for variation in their band gap energies using Diffuse Reflectance Spectroscopy in the ultraviolet-visible region. Phase quantification and compositional studies were performed using Rietveld analysis of the X-Ray Diffraction patterns, Scanning Electron microscopy, and Energy Dispersive X-Ray Analysis. Due to 3d transition ion doping, the samples have brilliant colors, and the absorption edge of Zn 0.95 TM 0.05 O was found to shift towards the visible and ultraviolet-visible region. The blue and red shifts in band gaps observed for various transition metal ion-doped ZnO are discussed.