Figure 7
Photocurrent as a function of bias voltages between the metal electrodes.
(a) Photocurrent from a bare semi-insulating Si (111) substrate. (b) Photocurrent from a heterostructure of n-GaN NRs grown on a Si substrate without any graphene layer. (c) The n-GaN NR-graphene hybrid structure on a Si substrate exhibits an increase in photocurrent. The insets of Figs. 7a,b,c show the I–V characteristics of photoconductive channels with (red line) and without (dark line) a light source. (d) The photocurrent increased almost nine fold for the n-GaN NR-graphene hybrid structure compared to that of the heterostructure without a graphene layer; the inset shows the variation of the sensitivity with bias voltages for the three types of channels under study.
