Optical semiconductor element
First Claim
1. An optical semiconductor element comprising a thin film containing ZnO, said thin film having grain boundaries which are barriers providing exciton confinement and laser resonator mirrors, and said thin film emitting light in the UV range.
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Accused Products
Abstract
A ZnO thin film is fabricated on the c-surface of a sapphire substrate through use of a laser molecular beam epitaxy (MBE) method-which is effective for epitaxial growth of an oxide thin film through control at an atomic level. The thus-formed ZnO thin film has a considerably high crystallinity; the half width of an X-ray rocking curve was 0.06°. The thin film is of an n-type and has a carrier density of 4×1017 /cm3. The thin film fabricated in a state in which oxygen partial pressure is held constant at 10-6 Torr has a structure in which hexagon-shaped nanocrystals of uniform size are close-packed, reflecting the crystal behavior of a wurtzite type. Since in each nanocrystal there is observed a spiral structure formed by steps of a unit cell height (0.5 nm), the nanocrystals are considered to grow in a thermodynamically equilibrated state. The lateral size of the nanocrystal can be controlled within the range of approximately 50 to 250 nm. A II-oxide optical semiconductor element utilizes a zinc oxide thin film containing magnesium or cadmium in a solid-solution state. Through addition of magnesium or cadmium, the band gap of zinc oxide can be controlled within the range of 3 to 4 eV.
164 Citations
22 Claims
- 1. An optical semiconductor element comprising a thin film containing ZnO, said thin film having grain boundaries which are barriers providing exciton confinement and laser resonator mirrors, and said thin film emitting light in the UV range.
- 5. A II-oxide optical semiconductor element which comprises a zinc oxide thin film containing magnesium in a solid solution or mixed phase state, said magnesium raising the band gap of said zinc oxide and said thin film having grain boundaries which are barriers providing exciton confinement and laser resonator mirrors, and said thin film emitting light in the UV range.
- 6. A II-oxide optical semiconductor element which comprises a zinc oxide film containing cadmium in a solid solution or mixed phase state. said cadmium lowering the band gap of said zinc oxide and having grain boundaries which are barriers providing exciton confinement and laser resonator mirrors, and said thin film emitting light in the UV range.
- 9. An optical semiconductor element comprising a ZnO light emitting layer, a p-type zinc oxide layer, an electrode and a thin film of AlCuO2 as an intermediate layer disposed between the p-type zinc oxide layer and the electrode.
Specification