Narrow-gap semiconductor detectors and lasers

Abstract

The major applications of narrow-gap materials continue to be in infrared detectors for passive imaging and in diode lasers, primarily for high resolution spectroscopy and related uses. The development of sophisticated epitaxial growth and fabrication techniques is continually expanding the capability of both types of devices. Background-limited HgCdTe and Pb-salt photodiodes and diode arrays have been developed for detection in the 8–12 μm wavelength range. High speed (> 1 GHz) HgCdTe photodiodes with sensitivities close to the quantum limit have been developed for heterodyne detection. The feasibility of PbS and HgCdTe CCIDs has been investigated for advanced imaging applications.

In the Pb-salt laser area the temperature for cw operation has been increased well beyond 100K by the use of heterostructures, significantly higher output powers and longer lifetimes have been achieved and DFB structures have been developed. Advances in various epitaxial growth techniques in both HgCdTe and the Pb-salts and the demonstration of low-loss Pb-salt waveguides at 10 μm indicate that sophisticated integrated optical circuits could be developed in these materials for long wavelength optical communications and related applications.