An electroabsorption modulated laser having a first face, a second face, an optical cavity and an active region, the optical cavity being defined by a semiconductor substrate and having a length extending between the first face and the second face, and the active region being configured for injection of charge into the cavity and having effective bandgap energies at respective distances along the length of the cavity, the electroabsorption modulated laser comprising a first modulator section extending between a first position and a second position and comprising a first part of the active region, and a second modulator section extending between the second position and a third position and comprising a second part of the active region, wherein the bandgap energy of the first part of the active region adjacent the first position is higher than the bandgap energy adjacent the second position.

A light-emitting element includes: a laminated structure body 20 which is formed from a GaN-based compound semiconductor and in which a first compound semiconductor layer 21 including a first surface 21a and a second surface 21b that is opposed to the first surface 21a, an active layer 23 that faces the second surface 21b of the first compound semiconductor layer 21, and a second compound semiconductor layer 22 including a first surface 22a that faces the active layer 23 and a second surface 22b that is opposed to the first surface 22a are laminated; a first light reflection layer 41 that is provided on the first surface 21a side of the first compound semiconductor layer 21; and a second light reflection layer 42 that is provided on the second surface 22b side of the second compound semiconductor layer 22. The first light reflection layer 41 includes a concave mirror portion 43, and the second light reflection layer 42 has a flat shape.

The invention relates to a method for fabricating a semiconductor structure. The method comprises fabricating a photonic crystal structure of a first material, in particular a first semiconductor material and selectively removing the first material within a predefined part of the photonic crystal structure. The method further comprises replacing the first material within the predefined part of the photonic crystal structure with one or more second materials by selective epitaxy. The one or more second materials may be in particular semiconductor materials. The invention further relates to devices obtainable by such a method.

A method of incorporating a control structure within a VCSEL device cavity using a multiphase growth sequence includes forming a first mirror over a substrate, forming an active region over the first mirror, forming a spacer on a surface of the active region, forming a control structure on a surface of the spacer, and forming a second mirror over the control structure. The active region and the spacer are formed using a molecular beam epitaxy (MBE) process during an MBE phase of the multiphase growth sequence. The second mirror is formed using a metal-organic chemical vapor deposition (MOCVD) process during an MOCVD phase of the multiphase growth sequence. The control structure is formed using a chemical etching process during a transition period between the MBE phase and the MOCVD phase of the multiphase growth sequence.

A surface-emitting laser element includes: a first guide layer including a photonic crystal layer that is formed on a c plane of a group-3 nitride semiconductor and includes air holes arranged with two-dimensional periodicity in a plane parallel to the photonic crystal layer, and an embedding layer that is formed on the photonic crystal layer and closes the air holes; an active layer formed on the first guide layer; and a second guide layer formed on the active layer, wherein an air hole set including at least a main air hole and a sub-air hole smaller in size than the main air hole is arranged at each square lattice point in the plane parallel to the photonic crystal layer, and wherein the main air hole has a regular-hexagonal prism shape, a long-hexagonal prism shape, or an elliptic cylindrical shape with a major axis parallel to a <11-20> axis.

A nitride-based electronic device includes an oxide cladding layer, a nitride cladding layer, and a nitride active region layer arranged between the oxide cladding layer and the nitride cladding layer. First and second metal contacts are electrically coupled to the nitride active region layer. The nitride-based electronic device can be formed in a system in which a non-reactive chamber is arranged between an oxide reaction chamber and a nitride reaction chamber so that oxide and nitride layers can be grown without exposing the device to the environment between growth of the oxide and nitride layers.

A laser diode (1) includes an AlN single crystal substrate (11), an n-type cladding layer (12) formed on the substrate and including a nitride semiconductor layer having n-type conductivity, a light-emitting layer (14) formed on the n-type cladding layer and including one or more quantum wells, a p-type cladding layer (20) formed on the light-emitting layer and including a nitride semiconductor layer having p-type conductivity, and a p-type contact layer (18) formed on the p-type cladding layer and including a nitride semiconductor that includes GaN. The p-type cladding layer includes a p-type longitudinal conduction layer (16) that includes Al.sub.sGa.sub.1−sN (0.3≤s≤1), has a composition gradient such that the Al composition s decreases with increased distance from the substrate, and has a film thickness of less than 0.5 μm, and a p-type transverse conduction layer (17) that includes Al.sub.tGa.sub.1−tN (0<t≤1).

A method of manufacturing a vertical cavity surface emitting laser element including a first reflector including a nitride semiconductor multilayer film, the method includes: growing a first semiconductor layer consisting of a group III semiconductor containing aluminum and indium, the growing of the first semiconductor layer consisting of growing a first layer by supplying an aluminum source gas, an indium source gas, and a nitrogen source gas, and growing a second layer by supplying an aluminum source gas, an indium source gas, and a nitrogen source gas so that an indium composition ratio of the second layer is higher than an indium composition ratio of the first layer; and growing a second semiconductor layer consisting of gallium nitride. The growing of the first semiconductor layer and the growing of the second semiconductor are repeated alternately to form the nitride semiconductor multilayer film constituting the first reflector.

A light emitting device, includes a selective growth mask layer 44; a first light reflection layer 41 thinner than the selective growth mask layer 44; a laminated structure including a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22, the first compound semiconductor layer 21 being formed on the first light reflection layer 41; and a second electrode 32 formed on the second compound semiconductor layer 22, and a second light reflection layer 42, in which the second light reflection layer 42 is opposed to the first light reflection layer 41, and the second light reflection layer is not formed on an upper side of the selective growth mask layer 44.

A light-emitting device that includes a substrate, and at least one column portion, wherein the column portion includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type different from the first conductivity type, and a light-emitting layer provided between the first semiconductor layer and the second semiconductor layer, the first semiconductor layer is provided between the substrate and the light-emitting layer, the light-emitting layer includes a first well layer, and a barrier layer, the barrier layer includes a first layer provided between the first semiconductor layer and the first well layer, and the first layer has a cubic crystal structure.