Wafer-scale transfer-free process of multi-layered graphene grown by chemical vapor deposition

Chemical vapour deposition (CVD) has emerged as the dominant technique to combine high quality with large scale production of graphene. The key challenge for CVD graphene remains the transfer of the film from the growth substrate to the target substrate while preserving the quality of the material. Avoiding the transfer process of single or...

Low Temperature CVD Grown Graphene for Highly Selective Gas Sensors Working under Ambient Conditions

In this paper we report on gas sensors based on graphene grown by Chemical Vapor Deposition at 850 °C. Mo was used as catalyst for graphene nucleation. Resistors were directly designed on pre-patterned Mo using the transfer-free process we recently developed, thus avoiding films damage during the transfer to the target substrate. Devices...

An innovative approach to overcome saturation and recovery issues of CVD graphene-based gas sensors

<br/>In this work, we present an innovative method which enables to solve fundamental limitations affecting graphene-based chemi-sensors operating under environmental conditions, namely the lack of signal saturation and the scarce recovery after the detection step. The method, which exploits the differential current instead of the current itself...

Lateral gas phase diffusion length of boron atoms over Si/B surfaces during CVD of pure boron layers

The lateral gas phase diffusion length of boron atoms, LB, along silicon and boron surfaces during chemical vapor deposition(CVD) using diborane (B2H6) is reported. The value of LB is critical for reliable and uniform boron layer coverage. The presented information was obtained experimentally and confirmed analytically in the...

High sensitive gas sensors realized by a transfer-free process of CVD graphene

The work herein presented investigates the behavior of graphene-based gas sensors realized by using an innovative way to prepare graphene. The sensing layer was directly grown by chemical vapor deposition on pre-patterned CMOS compatible Mo catalyst and then it was eased on the underlying SiO2 through a completely transfer-free process. Devices...

Low Temperature PureB Technology for CMOS Compatible Photodetectors

In this thesis, conventional high temperature (HT, 700 °C) PureB technology is optimized in order to fabricate detectors with improved key parameters such as the spatial uniformity of the responsivity. A novel technology for low temperature (LT, 400 °C) boron deposition is developed providing a uniform, smooth, closed LT boron layer. This...

Chemical vapor deposition of graphene: A route to device integration

In this thesis, I have shown that the quality of synthetic graphene can be as high as mechanically exfoliated graphene if we can get rid of the wrinkles. Any defects, impurities and grain boundaries will induce scattering, preventing ballistic transport. The experiment described in chapter 4 was the first to demonstrate ballistic transport in...

Efficient numerical methods for the instationary solution of laminar reacting gas flow problems

In production processes of micro-electronics, optical and mechanical coatings and solar cells, high-purity materials in the form of a powder or a thin film are significant importance. The deposition of thin films on irregularly shaped surfaces can be done by chemical vapor deposition (CVD). Computer simulations are widely used to design CVD...

Numerical Methods for Reacting Gas Flow Simulations

In this study various numerical schemes for simulating 2D laminar reacting gas flows, as typically found in Chemical Vapor Deposition (CVD) reactors, are proposed and compared. These CVD systems are generally modeled by means of many stiffly coupled elementary gas phase reactions between a large number of reactants and intermediate species. The...

Numerical Methods for Reacting Gas Flow Simulations

In this study various numerical schemes for simulating 2D laminar reacting gas flows, as typically found in Chemical Vapor Deposition (CVD) reactors, are proposed and compared. These CVD systems are generally modeled by means of many stiffly coupled elementary gas phase reactions between a large number of reactants and intermediate species. The...

High temperature silicon carbide chemical vapor deposition processes: From pure thermodynamic to mass transport modeling

Over the last twenty years, processes which lead to materials synthesis from a gaseous phase constitute an important technology in many applications fields such as microelectronics or protective coating industry. Due to the complexity of the involved phenomena, computational modeling had been required to improve technological processes and help...

Expanding thermal plasma deposition of hydrogenated amorphous silicon for solar cells

Abstract not available

Novel contacts and diodes for advanced silicon technology