Since the early seventies a considerable R. and D. effort has been devoted to high power LED structures for applications as transmitting sources in optical fibre communication systems. The objective of high power operation requires the development of a device technology to provide high internal efficiency, minimum absorption within the semiconductor chip and efficient heat sinking to prevent excessive temperature rise within the device. The first two requirements are achieved by the choice of a direct gap semiconductor, optimisation of the acceptor and donor doping profiles and optimisation of the chip geometry. To achieve adequate heat sinking many of the techniques used in high-power, solid-state microwave devices have been applied to the LED to locate the active region in close proximity to a high thermal conductivity heat sink and to ensure low impedance interfaces between chip, contacts and heat sink without introducing significant damage or strain in the active region of the device.
© 1977 Optical Society of AmericaPDF Article