Abstract
Van der Waals resonant tunneling diodes (vdW RTDs) with an N-shaped I–V characteristic enable the development of highly efficient components for data processing and transmission systems. The behavior of a vdW RTD as a dynamic system depends significantly on the total resistance R of the graphene layers and the metal contacts to them, as well as the minimum absolute negative differential resistance RN of the I–V characteristic of the vdW heterojunction. The system can function as an oscillator if RN \( \gg \) R or as a trigger if RN \( \ll \) R. These cases have been fully investigated. The case of RN < R has been studied insufficiently, especially for R ≈ RN, when a vdW RTD as a dynamic system can exhibit both trigger and oscillator properties. This paper analyzes the “mixed” mode for the I–V characteristic of a vdW heterojunction represented by a cubic trinomial. Methods of the qualitative theory of differential equations are used. It is shown that the experimental I–V characteristic of a vdW RTD at RN < R has a rectangular loop and, when self-oscillations occur, can additionally exhibit a sloping plateau. A method for reconstructing the I–V characteristic of a heterojunction from the characteristic parameters of the experimental I–V characteristic of a vdW RTD is proposed. The results obtained for the I–V characteristic of a vdW heterojunction in the form of a cubic trinomial can be applied to real RTDs by approximating the falling section of the I–V characteristic of a vdW heterojunction by a cubic trinomial. These results can serve as a supplement to the theory and design of circuits containing tunneling diodes (TD circuits).
