Charge-injection imaging: Operating techniques and performances characteristics

Burke, H. K.; Michon, G. J.

doi:10.1109/t-ed.1976.18373

Cited by 31 publications

(3 citation statements)

References 6 publications

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“…This phenomenon can be understood as a photogating effect by the carriers in the Si substrate, such as that used in charge injection devices. 26,27 This work is expected to contribute to the development of high-sensitivity graphene-based phototransistors.…”

Section: Discussionmentioning

confidence: 99%

Giant Dirac point shift of graphene phototransistors by doped silicon substrate current

et al. 2016

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Graphene is a promising new material for photodetectors due to its excellent optical properties and high-speed response. However, graphene-based phototransistors have low responsivity due to the weak light absorption of graphene. We have observed a giant Dirac point shift upon white light illumination in graphene-based phototransistors with n-doped Si substrates, but not those with p-doped substrates. The source-drain current and substrate current were investigated with and without illumination for both p-type and n-type Si substrates. The decay time of the drain-source current indicates that the Si substrate, SiO2 layer, and metal electrode comprise a metal-oxide-semiconductor (MOS) capacitor due to the presence of defects at the interface between the Si substrate and SiO2 layer. The difference in the diffusion time of the intrinsic major carriers (electrons) and the photogenerated electron-hole pairs to the depletion layer delays the application of the gate voltage to the graphene channel. Therefore, the giant Dirac point shift is attributed to the n-type Si substrate current. This phenomenon can be exploited to realize high-performance graphene-based phototransistors.

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