Abstract: A method of fabricating a continuous wave semiconductor laser diode in the (Al,Ga,In)N materials system comprises: growing, in sequence, a first cladding region (4), a first optical guiding region (5), an active region (6), a second optical guiding region (7) and a second cladding region (8). Each of the first cladding region (4), the first optical guiding region (5), the active region (6), the second optical guiding region (7) and the second cladding region (8) is deposited by molecular beam epitaxy.

Abstract: A semiconductor light-emitting device fabricated in a nitride material system has an active region (5) disposed over a substrate (1). The active region (5) comprises a first aluminium-containing layer (12) forming the lowermost layer of the active region, a second aluminium-containing layer (14) forming the uppermost layer of the active region, and at least one InGaN quantum well layer (13) disposed between the first aluminium-containing layer (12) and the second aluminum-containing layer (14). The aluminium-containing layers (12,14) provide improved carrier confinement in the active region (5), and so increase the output optical power of the device. The invention may be applied to a light-emitting diode (11) or to a laser diode.

Abstract: A method of growing a p-type nitride semiconductor material having magnesium as a p-type dopant by molecular beam epitaxy (MBE), comprises supplying ammonia gas, gallium and magnesium to an MBE growth chamber containing a substrate so as to grow a p-type nitride semiconductor material over the substrate. Magnesium is supplied to the growth chamber at a beam equivalent pressure of at least 1 10-9 mbar, and preferably in the range from 1 10-9 mbar to 1 10-7 mbar during the growth process. This provides p-type GaN that has a high concentration of free charge carriers and eliminates the need to activate the magnesium dopant atoms by annealing or irradiating the material.

Abstract: The invention provides a method of growing an (In,Ga)N multilayer structure by molecular beam epitaxy. Each GaN or InGaN layer in the multilayer structure is grown at a substrate temperature of at least 650° C., and this provides improved material quality. Ammonia gas is used as the source of nitrogen for the growth process.