The development of silicon semiconductor technology has produced breakthroughs in electronics—from the microprocessor in the late 1960s to early 1970s, to automation, computers and smartphones—by downscaling the physical size of devices and wires to the nanometre regime. Now, graphene and related two-dimensional (2D) materials offer prospects of unprecedented advances in device performance at the atomic limit, and a synergistic combination of 2D materials with silicon chips promises a heterogeneous platform to deliver massively enhanced potential based on silicon technology. Integration is achieved via three-dimensional monolithic construction of multifunctional high-rise 2D silicon chips, enabling enhanced performance by exploiting the vertical direction and the functional diversification of the silicon platform for applications in opto-electronics and sensing. Here we review the opportunities, progress and challenges of integrating atomically thin materials with silicon-based nanosystems, and also consider the prospects for computational and non-computational applications. Progress in integrating atomically thin two-dimensional materials with silicon-based technology is reviewed, together with the associated opportunities and challenges, and a roadmap for future applications is presented.

Graphene and two-dimensional materials for silicon technology.

Graphene research has prospered impressively in the past few years, and promising applications such as high-frequency transistors, magnetic field sensors, and flexible optoelectronics are just waiting for a scalable and cost-efficient fabrication technology to produce high-mobility graphene. Although significant progress has been made in chemical vapor deposition (CVD) and epitaxial growth of graphene, the carrier mobility obtained with these techniques is still significantly lower than what is achieved using exfoliated graphene. We show that the quality of CVD-grown graphene depends critically on the used transfer process, and we report on an advanced transfer technique that allows both reusing the copper substrate of the CVD growth and making devices with mobilities as high as 350,000 cm2 V–1 s–1, thus rivaling exfoliated graphene.

Ultrahigh-mobility graphene devices from chemical vapor deposition on reusable copper

The recent isolation of atomically thin black phosphorus by mechanical exfoliation of bulk layered crystals has triggered an unprecedented interest, even higher than that raised by the first works on graphene and other two-dimensionals, in the nanoscience and nanotechnology community. In this Perspective, we critically analyze the reasons behind the surge of experimental and theoretical works on this novel two-dimensional material. We believe that the fact that black phosphorus band gap value spans over a wide range of the electromagnetic spectrum (interesting for thermal imaging, thermoelectrics, fiber optics communication, photovoltaics, etc.) that was not covered by any other two-dimensional material isolated to date, its high carrier mobility, its ambipolar field-effect, and its rather unusual in-plane anisotropy drew the attention of the scientific community toward this two-dimensional material. Here, we also review the current advances, the future directions and the challenges in this young research...

Black Phosphorus: Narrow Gap, Wide Applications

Integrated circuits based on complementary metal-oxide–semiconductors (CMOS) are at the heart of the technological revolution of the past 40 years, enabling compact and low-cost microelectronic circuits and imaging systems However, the diversification of this platform into applications other than microcircuits and visible-light cameras has been impeded by the difficulty to combine semiconductors other than silicon with CMOS Here, we report the monolithic integration of a CMOS integrated circuit with graphene, operating as a high-mobility phototransistor We demonstrate a high-resolution, broadband image sensor and operate it as a digital camera that is sensitive to ultraviolet, visible and infrared light (300–2,000 nm) The demonstrated graphene–CMOS integration is pivotal for incorporating 2D materials into the next-generation microelectronics, sensor arrays, low-power integrated photonics and CMOS imaging systems covering visible, infrared and terahertz frequencies Graphene–quantum dots on CMOS sensor offers broadband imaging

Broadband image sensor array based on graphene–CMOS integration

Graphene has contributed to the fabrication of sensitive sensors and biosensors due to its physical and electrochemical properties. This review discusses the role of graphene and graphene related materials for the improvement of the analytical performance of sensors and biosensors. This paper also provides an overview of recent graphene based sensors and biosensors (2012–2016), comparing their analytical performance for application in clinical, environmental, and food sciences research, and comments on future and interesting research trends in this field.

Graphene based sensors and biosensors

Graphene/silicon CMOS hybrid integrated circuits (ICs) should provide powerful functions which combines the ultra-high carrier mobility of graphene and the sophisticated functions of silicon CMOS ICs. But it is difficult to integrate these two kinds of heterogeneous devices on a single chip. In this work a low temperature process is developed for integrating graphene devices onto silicon CMOS ICs for the first time and a high performance graphene/CMOS hybrid Hall IC is demonstrated. Signal amplifying/process ICs are manufactured via commercial 0.18 um silicon CMOS technology and graphene Hall elements (GHEs) are fabricated on top of the passivation layer of the CMOS chip via a low-temperature micro-fabrication process. The sensitivity of the GHE on CMOS chip is further improved by integrating the GHE with the CMOS amplifier on the Si chip. This work not only paves the way to fabricate graphene/Si CMOS Hall ICs with much higher performance than that of conventional Hall ICs, but also provides a general method for scalable integration of graphene devices with silicon CMOS ICs via a low-temperature process.

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Graphene/Si CMOS Hybrid Hall Integrated Circuits

Hall elements were fabricated based on high quality chemical vapor deposition grown graphene, and their performance limit was explored. The as-fabricated graphene Hall element exhibits current-related sensitivity of up to 2093 V/AT under 200 μA, and magnetic resolution of around 1 mG/Hz0.5 at 3 kHz. This ultrahigh sensitivity and resolution stem from high carrier mobility, small Dirac point voltage of 3 V, and low carrier density of about 3 × 1011 cm−2 in graphene device. The current sensitivity is found to decrease with increasing current bias at large bias, and this phenomenon is attributed to the drain induced Dirac point shift effect in graphene channel.

Ultra-sensitive graphene Hall elements

Chemical vapor deposition (CVD) is considered the most promising method for pushing graphene into commercial products. However, CVD grown graphene is usually of low quality. In this work we explore how good can CVD-derived monolayer graphene be. Through the combinational optimization of the main processes of growth, transfer, device fabrication and measurements, we show that the optimized CVD graphene can present performance comparable to mechanical exfoliated ones: in particular, high carrier mobility at room temperature on the Si/SiO2 substrate, perfect electron–hole symmetry and excellent uniformity (the mobility ranged from 5000 to 12 000 cm2 V−1 s−1 with an average mobility of ∼8800 cm2 V−1 s−1 and 50% were higher than 10 000 cm2 V−1 s−1). In addition we found that the adsorbed oxygen and water molecules on graphene lead to p-type doping in graphene, and transferred charges bring charged impurity scattering to the transporting carriers in the graphene channel. It is therefore necessary to carry out electrical measurements under vacuum to obtain high intrinsic carrier mobility CVD grown graphene.

How good can CVD-grown monolayer graphene be?

Multifunctional graphene magnetic/hydrogen sensors are constructed for the first time through a simple microfabrication process. The as-fabricated graphene sensor may act as excellent Hall magnetic...

Multifunctional graphene sensors for magnetic and hydrogen detection.

In this study, we correlated the angular dependence of the Raman response of black phosphorus to its crystallographic orientation by using transmission electron microscopy and Raman spectroscopy. It was found that the intensity of the Ag2 mode reached a maximum when the polarization direction of the incident light was parallel to the zigzag crystallographic orientation. Notably, it was further confirmed that the zigzag crystallographic direction exhibited superior conductance and carrier mobility. Because of the lattice extension along the armchair direction, an intensification of the anisotropic Raman response was observed. This work provides direct evidence of the correlation between anisotropic properties and crystallographic direction and represents a turning point in the discussion of the angular-dependent electronic properties of black phosphorus.

Probing the anisotropic behaviors of black phosphorus by transmission electron microscopy, angular-dependent Raman spectra, and electronic transport measurements

Xiaomeng Ma

Papers

Graphene/Si CMOS Hybrid Hall Integrated Circuits

Ultra-sensitive graphene Hall elements

How good can CVD-grown monolayer graphene be?

Multifunctional graphene sensors for magnetic and hydrogen detection.

Probing the anisotropic behaviors of black phosphorus by transmission electron microscopy, angular-dependent Raman spectra, and electronic transport measurements