P-type layers of a GaN based light-emitting device are optimized for formation
of Ohmic contact with metal. In a first embodiment, a p-type GaN transition layer
with a resistivity greater than or equal to about 7 cm is formed between
a p-type conductivity layer and a metal contact. In a second embodiment, the p-type
transition layer is any III-V semiconductor. In a third embodiment, the p-type
transition layer is a superlattice. In a fourth embodiment, a single p-type layer
of varying composition and varying concentration of dopant is formed.
