Fully Suspended Reduced Graphene Oxide Photodetector with Annealing Temperature-Dependent Broad Spectral Binary Photoresponses

Abstract

A series of fully suspended reduced graphene oxide (RGO) photodetectors were fabricated based on free-standing thermally reduced graphene oxide (GO) thin films with various annealing temperatures (from 200 to 1000 °C). A new phenomenon was found that under ultraviolet (375 nm) to near-infrared (1064 nm) lasers irradiations, the photodetector consisting of fully suspended thermally reduced graphene oxide thin film and Au interdigital electrodes possess positive or zero or negative response depending on the annealing temperature of GO. This may originate from the competition between annealing temperature-dependent the positive photoresponse from RGO and the negative photoconductivity of Au interdigital electrodes. The annealing temperature-dependent wide spectral binary photoresponse offers a good thinking for designing RGO-based light triggered logic devices. Moreover, upon visible (405 nm) to near-infrared (1064 nm) irradiations, all fully suspended RGO detectors prepared at various annealing temperatures exhibit fast photoresponse, that is, rise time is only tens of milliseconds, which are 1–4 orders of magnitude faster than the reported photodetectors based on supported RGO film and are on the same order of magnitude as the supported CVD-grown and supported mechanically exfoliated graphene photodetectors. The fast photoresponse originates from the fully suspended construction of device and the thin thickness of film, which provides a new design idea for fast response RGO-based device.

High-speed femtosecond laser plasmonic lithography and reduction of graphene oxide for anisotropic photoresponse

“…4e. R is almost invariable at~0.7 mA W −1 , which is numerically comparable to the response of samples obtained by other reduction methods (e.g., chemical and thermal) and much larger than that of typical photoreduced samples [31][32][33] . However, the photoresponse speed of our samples is relatively slow, as shown by the temporal measurement in Fig.…”

“…Our devices can realize stable photoresponsivity (R~0.7 mA W −1 ) even when exposed to light with low power (0.1 mW). This is numerically comparable to the response of samples obtained by other reduction methods (e.g., chemical and thermal) but is much larger than that of typical photoreduced samples [31][32][33] . In addition, the different reduction degrees of rGO along and vertical to the grating structures lead to its in-plane effective refractive indexes being different in the two directions, which in turn lays the foundation for the anisotropic response of rGO photodetectors 34 .…”

“…As a matter of fact, through modulation of the GO reduction degree and structural design of the rGO surface, we can change the properties of the rGO film, which allows us to further apply the material to optoelectronic applications. For example, the periodic grating structures have obvious optical trapping and grating coupling effects, which enhance the light absorption by~20% compared with the smooth surface 5 , and the light-active property of rGO also makes it suitable for realizing a photoresponse over a wide spectrum [31][32][33] . Our devices can realize stable photoresponsivity (R~0.7 mA W −1 ) even when exposed to light with low power (0.1 mW).…”

Graphene oxide films for advanced ultra-flat optical devices and photonic integrated circuits

“…Since pristine GO is a dielectric with low electronic conductivity and light absorption, it cannot be directly used for photo detection. Nevertheless, the reduction of GO is a more scalable and cost-effective approach for mass production of graphene-like materials as compared with the traditional mechanical and vacuum-based preparation methods, enabling many PDs based on rGO [171][172][173][174][175][176][177][178][179][180][181][182][183][184]. Moreover, rGO also has its own advantages such as high flexibility in engineering its material properties and great compatibility with a variety of substrates.…”

“…18(e)), which allowed efficient transfer of photogenerated charge carriers and ultimately resulted in high photo responsivity (1520 mA/W) and fast response time (on the order of 10 -3 s). In 2017, Gan et al [183] demonstrated fully suspended rGO PDs with different annealing temperatures (Fig. 18(f)…”