Solution-grown epitaxial InP for high-efficiency circuit-controlled microwave oscillators

High-purity epitaxial InP has been prepared by solution growth with free-donor concentrations of 2×1015 cm¿3 and liquid-nitrogen mobility of 49 000 cm2/Vs. The growth technique is described and the electrical properties of the layers are given. The microwave characteristics of diodes made on this material are described, and these, together with experiments on specially constructed diodes, suggest that a circuit-controlled bulk negative-resistance mode can be set up in this material. Devices have been produced which give up to 16% efficiency when operated in coaxial circuits at X band.