Semiconductor light emitting element

A semiconductor light emitting element comprising:

• an active layer for emitting first light by current injection;
• and
• a light absorbing and emitting selection for absorbing one part of the first light and for emitting second light having a greater peak wavelength than the first light,
• wherein a difference in peak wavelength between the first light and the second light is smaller than 0.9 times a half width of a spectrum of the first light.

A semiconductor light emitting element comprising:

• a GaAs substrate opaque to first light having a wavelength of λ;
• a light absorbing and emitting section formed on said GaAs substrate and matching in lattice with said GaAs substrate, said light absorbing and emitting section comprising an alternate lamination of first and second layers, each of said first layers having a reflective index of n1 and a thickness of λ/4n1, each of said second layers having a refractive index of n2 (n2<n1) and a thickness of λ/4n2, each of said second layers having a greater band gap than each said first layer;
• a first conductive-type clad layer formed on said light absorbing and emitting section and made of a semiconductor matching in lattice with said GaAs substrate;
• an active layer formed on said first conductive-type clad layer and made of a semiconductor matching in lattice with said GaAs substrate for emitting the first light having a peak wavelength of λ by current injection, said active layer having a band gap greater than each of said first layers of said light absorbing and emitting selection and smaller than said first conductive-type clad layer;
• said light absorbing and emitting section absorbing one part of the first light from said active layer and emitting second light having a greater peak wavelength than the first light, said light absorbing and emitting section also reflecting a remaining part of the first light from said active layer;
• and
• a second conductive-type clad layer formed on said active layer and made of a semiconductor matching in lattice with said GaAs substrate, said second conductive-type clad layer having a greater band gap than said active layer.

A semiconductor light emitting element comprising:

• a substrate made of any one of sapphire, GaN and SiC;
• a light absorbing and emitting section formed on said substrate and comprising an alternate lamination of first and second layers, each of said first and second layers being made of a gallium nitride compound semiconductor, each of said first layers having a refractive index of n1, and a thickness of λ/4n1, each of said second layers having a refractive index of n2 (n2<n1) and a thickness of λ/4n2, each of said second layers having a greater band gap than each said first layer;
• a first conductive-type clad layer formed on said light absorbing and emitting section and made of a gallium nitride compound semiconductor;
• an active layer formed on said first conductive-type clad layer and made of a gallium nitride compound semiconductors, said active layer omitting first light having a peak wavelength of λ by current injection, said active layer having a greater band gap than each of said first layers of said light absorbing and emitting section and smaller than said first conductive-type clad layer;
• said light absorbing and emitting section absorbing one part of the first light from said active layer and emitting second light having a greater peak wavelength than the first light, said light absorbing and emitting section also reflecting a remaining part of the first light from said active layer;
• and
• a second conductive-type clad layer formed on said active layer and made of a gallium nitride compound semiconductor, said second conductive-type clad layer having a greater band gap than said active layer.

A semiconductor light emitting element comprising:

• a substrate made of any one of Si and GaAs, said substrate being opaque to first light having a wavelength of λ;
• a light absorbing and emitting section formed on said substrate and comprising an alternate lamination of first and second layers, each of said first and second layers being made of a gallium nitride compound semiconductor, each of said first layer having a refractive index of n1 and a thickness of λ/4n1, each of said second layers having a refractive index of(n2<n1) and a thickness of λ/4n2, each of said second layers having a greater band gap than each said first layer;
• a first conductive-type clad layer formed on said light absorbing and emitting section and made of a gallium nitride compound semiconductor;
• an active layer formed on said first conductive-type clad layer and made of a gallium nitride compound semiconductors, said active layer emitting first light having a peak wavelength of λ by current injection, said active layer having a greater band gap than each of said first layers of said light absorbing arid emitting section and smaller than said first conductive-type clad layer;
• said light absorbing and emitting section absorbing one part of the first light from said active layer and emitting second light having a greater peak wavelength than the first light, said light absorbing and emitting section also reflecting a remaining part of the first light from said active layer;
• and
• a second conductive-type clad layer formed on said active layer and made of a gallium nitride compound semiconductors said second conductive-type clad layer having a greater band gap than said active layer.