Gas phase enhancement of emission color quality in solid state LEDs
Light-emitting materials are made from a porous light-emitting semiconductor having quantum dots (QDs) disposed within the pores. According to some embodiments, the QDs have diameters that are essentially equal in size to the width of the pores. The QDs are formed in the pores by exposing the porous semiconductor to gaseous QD precursor compounds, which react within the pores to yield QDs. According to certain embodiments, the pore size limits the size of the QDs produced by the gas-phase reactions. The QDs absorb light emitted by the light-emitting semiconductor material and reemit light at a longer wavelength than the absorbed light, thereby “down-converting” light from the semiconductor material.
1. A method for synthesizing quantum dots (QDs) in a light-emitting semiconductor material, the method comprising:
flowing gaseous QD precursors through first pores in a semiconductor material to effect reaction of the QD precursors in the absence of liquid solvent and grow a plurality of first QDs in the first pores having diameters essentially equal to the first pore diameters; and
flowing gaseous QD precursors through second pores in a semiconductor material to effect reaction of the QD precursors in the absence of liquid solvent and grow plurality of second QDs in the second pores having diameters essentially equal to the second pore diameters;
wherein the second pores have diameters larger than the diameters of the first pores.
2. The method of claim 1 , wherein the first pores and the second pores are about 1 nm to about 20 nm in diameter.
3. The method of claim 1 , wherein the light-emitting semiconductor material comprises as GaN, AlGaAs, AlGaInP, or AlGaInN, or any derivatives thereof.
4. The method of claim 1 , wherein the one or both of the first QDs and the second QDs comprise a semiconductor material selected from CdS, CdSe, ZnS, ZnSe InP, GaP Cd 3 P 2 and In 2 Se 3 .
5. The method of claim 1 , wherein the first QDs are green light-emitting QDs.
6. The method of claim 1 , wherein the second QDs are red light-emitting QDs.