Advanced Optical Detection through the Use of a Deformably Transferred Nanofilm.

Graphene has been extensively investigated in advanced photodetection devices for its broadband absorption, high carrier mobility, and mechanical flexibility. Due to graphene's low optical absorptivity (2.3%), graphene-based photodetection research so far has focused on hybrid systems to increase photoabsorption. However, such hybrid systems require a complicated integration process and lead to reduced carrier mobility due to heterogeneous interfaces. Crumpled or deformed graphene has previously been reported in electronics and optoelectronics. However, a depth study on the influence of the morphology of nanofilms (e.g., graphite or graphene) related to light absorption in photodetection devices has not been demonstrated yet. Here, we present an interesting study in terms of the effect of the deformable surface and the smooth surface of a nanofilm transferred onto Si through two transfer strategies using isopropanol injection and nitrogen blowing (to form a deformable nanofilm surface) and deionized water injection and van der Waals interaction (to form a smooth nanofilm surface). As a result, optical detection in the case of the deformable nanofilm surface was enhanced significantly (~100%) compared with that of the smooth nanofilm surface in the visible laser wavelength (532 nm). In addition, evidence from the computational simulation also firmly affirms an advancement in the optical detection of deformed nanofilm-surface-based photodetection devices compatible with the experimental results.