Luther M Foster

Indirect, Γ8v‐X1c, band gap in GaAs1−xPx

The indirect band gap of GaAs1−x P x has been determined accurately over a large alloy composition range. The results were obtained with a wavelength derivative technique in optical absorption on material grown under complete equilibrium conditions. Zero‐phonon as well as momentum‐conserving phonon‐assisted free‐exciton transitions were observed. A distinct curvature in the direct band gap‐vs‐alloy composition curve is determined. Photoluminescence measurements of the same samples, together with the absorption edge data, give the alloy composition dependences of the energies of donor‐acceptor pairs and bound excitons; thus the intrinsic nature of the transitions observed in absorption is established.

Preparation of Efficient Electroluminescent Diodes from p‐on‐n Liquid‐Phase Epitaxial Layers of GaP

Efficient red‐emitting GaP diodes have been fabricated from p‐on‐n layers formed by liquid epitaxy in a closed‐tube system. The external quantum efficiency may increase by a factor of two to three after the diodes are heat‐treated.