InP nanowire photodetectors heteroepitaxially grown between silicon electrodes

We demonstrate an InP nanowire based photodetector laterally integrated between two (111)-oriented vertical silicon surfaces. The nanowires are grown through a simple single step chemical vapor deposition (CVD) process using gold nanoparticles as catalyst with in-situ p-doping and have been heteroepitaxially bridged between a pair of prefabricated p-doped Si electrodes. Nonlinear current-voltage characteristics are observed. Although this nonlinearity resembles a back-to-back rectifying profile it originates from space-charge limited conductivity of the nanowires. DC photoelectric characteristics of the device were measured under optical illumination (lambda=630 nm) above the bandgap energy (1.34 eV or similar to 925 nm at room temperature) of InP. The variation in photoconductance with varying input optical power demonstrates high sensitivity of the device to optical illumination.