A hole concentration greater than 1020 cm−3 in GaAs has been achieved using a liquid CCl4 source for carbon in a low-pressure organometallic vapor phase epitaxy system. The resistivity and hole mobility measured at 300 K for a heavily carbon-doped (1.2×1020 cm−3) Hall sample made from a thin (180 nm) epitaxial layer were 8.0×10−4 Ω cm and 65 cm2/V s, respectively. Carbon-doped samples with excellent surface morphology were achieved using a V/III ratio of 22, and growth pressure and temperature of 80 Torr and 600 °C, respectively. A novel photoluminescence technique, based on band-gap shrinkage of heavily doped p+-GaAs, has been shown to be useful for nondestructive measurement of the hole concentration in submicrometer layers.

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Results of a study of the electrical derivative characteristics of InGaAsP buried heterostructure lasers are presented. By considering current-leakage paths and electrical contact nonlinearities, an equivalent circuit model appropriate to the buried heterostructure laser has been developed. Solutions for the theoretical electrical derivatives of series-parallel-reducible networks have been obtained and applied to the equivalent circuit model of the buried heterostructure laser. Comparison of experimentally measured and calculated electrical derivative characteristics provides both qualitative and quantitative information concerning the distribution of current and voltage in buried heterostructure lasers. By combining the techniques of electrical-derivative measurement and equivalent-circuit modelling, an improved understanding of the properties of buried heterostructure lasers has been established.

Discrete InGaAsP double heterostructure lasers (λ=1.3 μm) have been fabricated by a novel batch process which incorporates chemically etched end reflectors. The etched-mirror lasers have threshold current densities as low as 3.5 kA/cm2. The average threshold current density for the etched-mirror lasers is approxiamtely 40% higher than for standard cleaved-mirror devices fabricated from the same wafer. The laser fabrication process permits batch fabrication of a much wider variety of discrete laser geometries than conventional laser-cleaving techniques.

InGaAsP-InP heterojunction phototransistors have been fabricated by liquid phase epitaxy. The phototransistors have optical gains greater than 100 for 1.26-μm radiation. High internal current gains (≳300) have been achieved. Phototransistor relative spectral response has been measured for wavelengths in the range 0.7–1.5 μm.