Metal-insulator-semiconductor light modulators utilizing the Franz-Keldysh effect in gallium arsenide

A study was made of the electroabsorption kinetics, as well as of the spectral and field dependences of the contrast and efficiency of modulation of light in Al-SiO₂-GaAs-n⁺-GaP structures near the fundamental absorption edge of GaAs (875–910 nm). Values of the contrast amounting to 10–12 and the modulation efficiency of 30–40% were achieved. It was demonstrated that optical data storage was possible with the aid of an He-Ne laser. Optical memory was observed in Al-SiO₂-(n-n⁺-GaAs structures on application of voltage pulses causing carrier accumulation; the effect was due to the capture of electrons at the SiO₂-GaAs interface. The absorption edge of epitaxial GaAs films on GaP substrates had an exponential profile in the photon energy range 1.37h1.40 eV infields 0E 56.5·10⁴ V/cm. An empirical relationship was obtained for the spectral and field dependences of the absorption coefficient.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp.36–41, December, 1980.