Results 2015-2016

DC and microwave measurements

The measurements were performed with a vector network analyzer coupled to a probe station PM4 and with  the Keithley 4200 SCS staion cupled to VNA for DC and microwave characterization (see Fig.1, 2) .

Fig. 1 Test measurement station Fig. 2 Diode in the probe staion for measurement

DC measuremnts of the diode is displayed in Fig.3.The rectification and the nonlinear behaviour are evidencied clearly in the figure.


Fig.3 I-V dependence of the graphene diode.

S parameters were measured and losses were in the range 4-5 dB while a tunable phase shift with the applied DC voltage was measured in the range 40-65 GHz (see Fig. 4)

Fig. 4 Phase  S21 as a function of applied DC We have a phase shift of about 10 degrees /V.

1 Simulation of the DC equivalent circuit of the Schottky diode.

The equivalent circuit of the Schottky diode is depicted in Fig. 5

Fig. 5 Circuitul echivalent al diodei Schottky pe grafena.

The simulation was performed with AWR software and we have extracted the values of the equivalent DC components directly from measurement results.

Tabelul 1 Values of the equivalent circuit components

Tensiunea DC aplicata(V)


























2. The DC and microwave characterization of the graphene multiplier.

The graphene multiplier is prsented in Fig. 6 a and the measurement system in Fig. 6 b.
a b

In Fig. 7  we have represented the multiplier response at the inmput frequencies of 3, 5, 6 , 9 GHz.

Fig. 7 The response of the multiplier at: (a) 3 GHz ,(b) 5 GHz (c) 6 GHz (d) 9 GHz; input power 0dBm and 4V DC bias.

Annex 1 ISI papers published during the project with the mention “this work was supported by a grant of Romanian National Authority for Scientific Research, CNCS-UEFISCDI, Project number PN-II-IDPCE-2011-3-0071

  1. A. Radoi, M.Dragoman, A.Cismaru, G.Konstantinidis, and D.Dragoman, Self-powered microwave devices based on graphene ink decorated with gold nanoislands, J. Appl.Phys. 112, 064327 (2012).
  2. M.Dragoman, D. Neculoiu, A.Cismaru, G.Deligeorgis, G. Konstantinidis, and D.Dragoman, Graphene nanoradio: Detecting radiowaves with a single atom sheet, Appl. Phys. Lett. 109, 033109 (2012).
  3. M.Dragoman, G. Deligeorgis, A.Muller, A.Cimaru, D.Neculoiu, G. Konstantinidis, D.Dragoman, A.Dinescu and F. Comanescu, Millimeter wave Schottky diode on graphene monolayer via symmetric metal contacts, J. Appl. Phys. 112, 084302 (2012).
  4. M Dragoman, G Konstantinidis, K Tsagaraki, T Kostopoulos, D Dragoman and D. Neculoiu, Graphene-like metal-on-silicon field-effect transistor,  Nanotechnology 23 305201(2012).
  5. Mircea Dragoman, Alina Cismaru, Adrian Dinescu, Daniela Dragoman, G. Stavrinidis, and G. Konstantinidis, Enhancement of higher harmonics in graphene-based coupled coplanar line microwave multipliers, Journal of Applied Physics 114, 154304 (2013).
  6. M.Dragoman, Nanoelectronics on a single atom sheet, Romanian Reports in Physics, Vol. 65, No. 3, P. 792–804, 2013.
  7. Mircea Dragoman, Detection of electromagnetic waves with a single carbon atom sheet, Proc. Romanian Academy, series A . vol.15, pp.208-215 (2014).
  8. M. Dragoman, D. Neculoiu, Al.-C. Bunea, G. Deligeorgis, M. Aldrigo, D. Vasilache, A. Dinescu, G. Konstantinidis, D. Mencarelli, L. Pierantoni, and M. Modreanu, A tunable microwave slot antenna based on graphene, Appl. Phys. Lett. 106, 153101 (2015).
  9. M. Dragoman, A. Cismaru, M.  Aldrigo, A. Radoi, and D. Dragoman, Switching microwaves via semiconductor-isolator reversible transition in a thin-film of MoS2, J. Appl. Phys.  118, 045710 (2015).
  10. M. Aldrigo, M.Dragoman, Graphene rectenna for efficient energy harvesting at terahertz frequencies, Applied physics Letters 109, 113105 (2016)