NOVELTY - The device has a substrate (21) made of material with a hexagonal crystal structure and including a substrate axis, which is perpendicular to a principal surface of the substrate. Nitride-based group III-V compound semiconductor layers are grown directly on and in contact with the principal surface of the substrate without growing a buffer layer between the substrate and the nitride-based group III-V compound semiconductor layers, where directions of growth axes of the semiconductor layers are same as direction of the substrate axis of the substrate.    USE - Semiconductor device e.g. red/green/blue light emitting device such as LED and semiconductor laser (all claimed), for use in an electronic apparatus i.e. backlight, of an LCD panel. Can also be used as an electron transit device e.g. FET such as electron high-mobility transistor and bipolar transistor e.g. heterojunction bipolar transistor (HBT), photodiode, sensor and solar cell in an illuminator, display, light-source cell unit, projector, rear projection TV, grating light valve (GLV), cellular phone, mobile equipment, robot, personal computer, vehicle-loaded equipment and a domestic electrical appliance.    ADVANTAGE - The semiconductor layers are provided with flat surfaces and good crystallinity, and form device structures on the substrate without growing the buffer layer. The LED is manufactured without growing a low-temperature buffer layer, so that manufacturing steps can be simplified, thus reducing manufacturing cost. The device is provided with transparent resin that is in contact with rear surfaces of substrates of a green LED chip and a blue LED chip, so that difference in refractivity can be reduced, and proportion at which light passing through the substrate toward an outside is reflected at a rear surface of the substrate can be reduced, thus increasing efficiency in taking out the emitted light and light emission efficiency.    DETAILED DESCRIPTION - The semiconductor layers are n-type nitride-based III-V compound semiconductor layers (22, 23) and p-type nitride-based III-V compound semiconductor layers (25). The substrate is made of material selected from a group consisting of sapphire, silicon carbide, alpha-zinc sulfide and zinc oxide or nitride-based III-V compound semiconductor material.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a structure for manufacturing an LED.    Substrate (21)    N-type nitride-based III-V compound semiconductor layers (22, 23)    Active layer (24)    P-type nitride-based III-V compound semiconductor layers (25)    P-side electrode (26)