**Acknowledgements**

the ones of commercial terahertz detectors at room temperature like Golay cells, pyroelectric detectors, and Schottky diodes [47]. However, the Si/SiGe MODFET presents the advantage of

**Figure 10.** Responsivity (a) and NEP (b) measured under excitation of 0.15 (blue dots) and 0.3 THz (red squares) of the

**Hz) RV (V/W) NEP (nW/√**

**\_\_\_ Hz)**

To test the ability of the strained-Si MODFETs as detectors in THz imaging, a single transistor (D1) was used as the sensor in the terahertz imaging system shown in **Figure 3**. **Figure 11** shows the visible image of a standard copper RT/duroid® laminate where the logo of the Nanotechnology Group at Salamanca University has been etched (a) and its terahertz image at 0.3 THz (b) when it was wrapped around with a paper. THz radiation passes through in the regions were the metal layer was etched off and it is reflected in the regions covered with copper. A pixel-by-pixel image was taken using D1 as the detector; the gate of the transistor

**Figure 11.** Visible (a) and 0.3 THz (b) images obtained at room temperature using the strained-Si MODFET with a shorter

working at higher modulation frequencies as compared to other detectors.

**0.15 THz 0.3 THz**

Device 1 68.6 0.08 46.4 0.12 Device 2 74.5 0.06 36.2 0.13 Device 3 41.1 0.12 33.3 0.14

**\_\_\_**

**RV (V/W) NEP (nW/√**

**Table 2.** Calculated NEPs and RV for the different devices under studio.

strained-Si MODFET with 100-nm gate length.

66 Design, Simulation and Construction of Field Effect Transistors

gate as sensor.

We would like to acknowledge Thomas Hackbarth (Daimler AG) who fabricated the strained-Si MODFETs used in this work. Our work was financially supported by the Spanish Ministry of Economy and Commerce and FEDER (ERDF: European Regional Development Fund) under the Research Grant #TEC2015-65477-R and FEDER/Junta de Castilla y León Research Grant #SA045U16. Both Research Grants #TEC2015-65477-R and Salamanca University partly support Open Source publications. Y. M. Meziani acknowledges the financial support from RIEC nation-wide Collaborative Reseach Project, Sendai, Japan.
