Nitride-based white light emitting device and manufacturing method thereof

Abstract

A light emitting device includes an n-type cladding layer. a p-type cladding layer. an active layer interposed between the n-type cladding layer and the p-type cladding layer and an ohmic contact layer contacting the p-type cladding layer or the n-type cladding layer. The ohmic contact layer includes a first film that includes a transparent conductive zinc oxide doped with a rare earth metal and including a one-dimensional nano structure. The one-dimensional nano structure is one of a nano-column, a nano rod and a nano wire.

1 . A method of manufacturing a white light emitting device, the method comprising:
 forming an n-type cladding layer, an active layer, and a p-type cladding layer on a substrate, the active layer being interposed between the n-type cladding layer and the p-type cladding layer;   forming a transparent conductive zinc oxide film of an ohmic contact layer, the zinc oxide film being doped with at least one rare earth metal and including a nano structure;   and   heat treating the zinc oxide film.   
   
   
       2 . The method of  claim 1 , wherein the rare earth metal comprises one of Er, Sm, Ce, Pr, Pm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, Lu, Th, Pa, U, Np, Pu, Am, Bk, Cf, Es, Fm, Md, No, Lr, and Cm. 
   
   
       3 . The method of  claim 2 , wherein an amount of the rare earth metal is equal to or smaller than about 20 weight %. 
   
   
       4 . The method of  claim 1 , wherein the formation of the zinc oxide film comprising:
 depositing a two-dimensional thin film of zinc oxide; and   etching and re-growing the two-dimensional thin film under an atmosphere including a hydrogen gas.   
   
   
       5 . The method of  claim 1 , wherein the zinc oxide film comprises one of aluminum (Al), chromium (Cr), silicon (Si), germanium (Ge), indium (In), lithium (Li), gallium (Ga), magnesium (Mg), zinc (Zn), beryllium (Be), molybdenum (Mo), vanadium (V), copper (Cu), iridium (Ir), rhodium (Rh), ruthenium (Ru), tungsten (W), cobalt (Co), nickel (Ni), manganese (Mn), titanium (Ti), tantalum (Ta), cadmium (Cd), lanthanum (La), and oxides thereof. 
   
   
       6 . The method of  claim 2 , further comprising:
 forming an ohmic interlayer under the zinc oxide film,   wherein the ohmic interlayer comprises one of metals including Ni, Pd, Pt, Rh, Zn, In, Sn, Ag, Au, Cd, Mg, Be, Mo, V, Cu, Ti, Ir, Ru, W, Co, Mn, and La, transparent conductive oxides including ITO, SnO 2 , ZnO, In 2 O 3 , Ga 2 O 3 , RhO 2 , NiO, CoO, PdO, PtO, CuAlO 2 , CdO, and CuGaO 2 , and transparent conductive nitrides including TiN, TaN, and SiNx.   
   
   
       7 . The method of  claim 6 , further comprising:
 performing a heat treatment after the formation of the ohmic interlayer and before the formation of the zinc oxide film.   
   
   
       8 . The method of  claim 7 , wherein the heat treatment before the formation of the zinc oxide film is performed at a temperature equal to or lower than about 800° C. and under a vacuum or under an atmosphere of oxygen (O 2 ), nitrogen (N 2 ), argon (Ar), hydrogen (H 2 ), or air.