PICOSECOND GAAS AND INGAAS PHOTOCONDUCTIVE SWITCHES OBTAINED BY LOW-TEMPERATURE METAL-ORGANIC CHEMICAL VAPOR-DEPOSITION

High-resistivity GaAs and InGaAs layers have been obtained by the MOCVD growth technique at low temperatures for the first time. The structural and physical properties of the LT-MOCVD-grown GaAs layers were similar to those of annealed LT-MBE GaAs layers-they were of a high crystalline quality with mobilities reaching 2600 cm2 V-1 s-1 and had short carrier lifetimes of 50 ps. The resistivity of the LT-grown InGaAs layers was close to its intrinsic limits. Photoconductive switches with carrier lifetimes of 20 to 40 ps, long-wavelength cut-off of 1.7-mu-m, breakdown voltage of 10 V for a 5-mu-m gap and sensitivity reaching 0.05 A W-1 were fabricated from those layers.