Wurtzite structure gallium nitride, GaN,a direct bandgap semiconductor(3.4 eV at room temperature),is an ideal material for fabrication of blue/green light emit ting diodes(LED),laser diodes(LD),and high power integrated circuits.When used a s the material for LEDs and LDs,GaN has high transforming efficiencies and its d evice s have a long using lifetime of up to 10000 hours,several decuple times longer t han that of conventional light emitting diodes.As a semiconductor material for b lue/green light sources,GaN is non replaceable.It will have important applications in li g ht emitting devices,optical communication systems,compact disk(CD)players,full c olor copying devices,full color printers,high distinguishing laser printers,gr ea t screen full color displaying devices,and super thin TV displaying devices etc . In recent years,GaN has been the focus and hotspot of semiconductor industries,a nd its devices have a shining place in light emitting and laser industries. We synthesized GaN nanowires by a chemical vapor deposition (CVD)method.The nano wires have diameters from 20 nm to 60 nm,and the maximum length is up to 100 μ m .Following figure is the scanning electron microscopy (SEM)image of the as synt hesized GaN nanowires.
Wurtzite structure gallium nitride GaN,a direct bandgap semiconductor,is an ideal material for fabrication of blue/green light emitting diodes,laser diodes, and high powder Integrated Circuites.Up to now,small single crystals,powders and nanomaterials of GaN have successfully synthesized as well as applied films gro wn by MOCVD.In this report,another condensed state of GaN,nanocrystal assembled bulk,was synthesized and its spectra are investigated. Metal gallium or gallium alloys are used as starting materials and haloids used as catalyzer in ammonia.Buff transparent GaN bulks were obtained at 350—500℃.P owder X ray diffraction indicated that the bulks are wurtaite GaN single phase. HRTEM confirmed that the bulks are composed of nanoparticles with average size o f 12mm.The well crystallized particle shows clear diffraction spots.PL spectra of the material are similar to that of GaN singe crystals under the ultraviolet excitation,but blue shift is observed near gap band.Red shift occurs in Raman scattering comparing with single crystals.The materials have the broad potential in the future because it not only possesses of mechanical and optical characteri stics owned by single crystals but also holds the nano properties of the nanoma terials.
