Persistent photoconductivity of InP nanowire photoconductors bridged between amorphous silicon electrodes

Ataur Sarkar; Logeeswaran V. J.; Nobuhiko P. Kobayashi; Joseph Straznicky; Shih-Yuan Wang; R. Stanley Williams; M. Saif Islam

doi:10.1117/12.752679

10 October 2007 Persistent photoconductivity of InP nanowire photoconductors bridged between amorphous silicon electrodes

Ataur Sarkar, Logeeswaran V. J., Nobuhiko P. Kobayashi, Joseph Straznicky, Shih-Yuan Wang, R. Stanley Williams, M. Saif Islam

Author Affiliations +

Proceedings Volume 6768, Nanomaterials Synthesis, Interfacing, and Integrating in Devices, Circuits, and Systems II; 67680P (2007) https://doi.org/10.1117/12.752679
Event: Optics East, 2007, Boston, MA, United States

Abstract

We fabricated a photo-conducting device with InP nanowires bridged between phosphorous-doped hydrogenated amorphous silicon electrodes. Photoresponse of the device with DC bias was characterized with a white light source and a 630nm He-Ne laser. Experimental results from a large number of devices demonstrate a persistent photoconductivity, a very unique feature of interest. After the light source is shut off, the photogenerated excess carriers recombine very slowly over time and the effect is manifested in the form of persistent photocurrent that takes hours to decay to the dark current level in the range of ~15 nA. Quasi exponential decay of the persistent photocurrent is observed with higher decay rate at the initial stage just after the light source is turned off. Persistent photocurrent magnitude varies with the magnitude of bias voltage, intensity and wavelength of the optical illumination. Experimental decay constant is determined from 0.237/min for -8V bias to 0.174/min for -2V bias. The long recombination time can be attributed to the carrier trapping in the light-induced traps, defects in nanowires and/or in the interface between the nanowires and the amorphous silicon electrodes. Slow recombination process may also originate from the spatial separation of photogenerated electrons and holes by built-in electric fields due to band bending at the heterostructure interfaces between InP nanowire and amorphous silicon electrodes.

Citation Download Citation

Ataur Sarkar, Logeeswaran V. J., Nobuhiko P. Kobayashi, Joseph Straznicky, Shih-Yuan Wang, R. Stanley Williams, and M. Saif Islam "Persistent photoconductivity of InP nanowire photoconductors bridged between amorphous silicon electrodes", Proc. SPIE 6768, Nanomaterials Synthesis, Interfacing, and Integrating in Devices, Circuits, and Systems II, 67680P (10 October 2007); https://doi.org/10.1117/12.752679

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