The University of Texas System

Consiglio Nazionale Delle Ricerche

Deji Akinwande

Seyedeh Maryam Mortazavi Zanjani

Mir Mohammad Sadeghi

Milo Holt

Nanshu Lu

Li Tao

Alessandro Molle

Shideh Kabiri Ameri Abootorabi

Carlo Grazianetti

Nanomaterial epidermal sensors can be adhered to the skin and worn comfortably and inconspicuously for days to allow for repeated biometric sensing. The nanomaterial epidermal sensors may be comprised of a monolayer of graphene coating a flexible polymer substrate. Various nanomaterial epidermal sensors may be quickly fabricated using a cost-efficient 'cut-and-paste' method on transfer paper and can be adhered directly to skin without tape or adhesive, much like a temporary-tattoo. The nanomaterial epidermal sensors may be optically transparent and may be used to measure an electrocardiogram (ECG), an electroencephalogram (EEG) or an electromyogram (EMG) with a signal-to-noise ratio that is comparable to conventional electrodes. In addition, the nanomaterial epidermal sensors may be used to measure other parameters, such as skin temperature or skin hydration.

Nanomaterial epidermal sensors

A field-effect transistor and method for fabricating such a field-effect transistor that utilizes an air-sensitive two-dimensional material (e.g., silicene). A film of air-sensitive two-dimensional material is deposited on a crystalized metallic (e.g., Ag) thin film on a substrate (e.g., mica substrate). A capping layer of insulating material (e.g., aluminum oxide) is deposited on the air-sensitive two-dimensional material. The substrate is detached from the metallic thin film/air-sensitive two-dimensional material/insulating material stack structure. The metallic thin film/air-sensitive two-dimensional material/insulating material stack structure is then flipped. The flipped metallic thin film/air-sensitive two-dimensional material/insulating material stack structure is attached to a device substrate followed by having the metallic thin film etched to form contact electrodes. In this manner, the pristine properties of air-sensitive two-dimensional materials are preserved from degradation when exposed to air. Furthermore, this new technique allows safe transfer and device fabrication of air-sensitive two-dimensional materials with a low material and process cost.

Integration of air-sensitive two-dimensional materials on arbitrary substrates for the manufacturing of electronic devices

The integration of monolayer graphene with a semiconductor device for gas sensing applications involves obtaining a CMOS device that is prepared to receive monolayer graphene channels. After population of the monolayer graphene channels on the CMOS device, electrical contacts are formed at each end of the monolayer graphene channels with interconnect vias having sidewalls angled at less then 90&#xb0;. Additional metallization pads are added at the location of the monolayer graphene channels to improve planarity and reliability of the semiconductor processing involved.

Integration of monolayer graphene with a semiconductor device

The sensitivity of a graphene gas sensor to a gas analyte molecule may be significantly enhanced using molecular doping, which may be as effective as substitutional doping and more effective than electric-field doping. In particular, the room temperature sensitivity of NO-doped graphene to NHwas measured to be comparable to the sensitivity of graphene doped with substitutional boron atoms and superior to that of undoped graphene by an order of magnitude. The detection limit for NO-doped graphene gas sensors was estimated to be about 200 ppb, which may be improved with extended exposure to NO, compared to a detection limit of about 1.4 ppm for undoped graphene. While the stability analysis of NO-doped graphene sensors indicates that the doping method may not be completely stable, molecular doping is nevertheless a candidate technique for sensitivity improvement by enhancing the initial carrier concentration.

Growing community of inventors

Austin, TX, United States of America

Deji Akinwande