High performance planar GaAs/Al0.3Ga0.7As Schottky barrier photodetector grown on Si substrates by molecular beam epitaxy

A high-speed and high sensitivity planar GaAs/Al_0.3Ga_0.7As heterostructure Schottky barrier photodiode grown on p-type silicon substrate by molecular beam epitaxy (MBE) has been studied. Growth of a thermally strained superlattice (TSL) buffer layer enables the fabrication of high performance GaAs Schottky photodiodes on silicon substrate. A reverse leakage current of 9*10^-10 A was obtained at -5 V. The detector responsivity and quantum efficiency measured at 0.84 mu m were found to be 0.25 A/W and 327.5%, respectively. The response speed of this photodiode measured by the impulse response method, has a 70 ps risetime and a 3 dB bandwidth of 5 GHz.