Negative differential resistance and rectification effect of the benzoquinone molecules junction sandwiched between the graphene nanoribbon electrodes

Abstract

Based on the first-principles calculation method combining the density functional theory (DFT) and the nonequilibrium Green’s function (NEGF) method, the negative differential resistance (NDR) and rectification effect of the benzoquinone molecules junction sandwiched between the graphene nanoribbon electrodes are systematically investigated. The current of the device with the central o-benzoquinone and p-benzoquinone molecule has been demonstrated to decrease with the increase of the bias voltage in the range of [± 0.9 V, ± 1.5 V] and [± 0.6 V, ± 1.1 V], respectively, exhibiting a significant NDR effect. In addition, the interesting NDR effect of the device with the central carbon (C) and nitrogen (N) connected o- and p-benzoquinone molecules has been observed in the bias voltage range of [0.9 V, 1.2 V] and [ $$-0.8$$  V, $$-1.0$$  V] , respectively. The current of the device with the central sulfur (S) and oxygen (O) connected o- and p-benzoquinone molecules should decrease with the increase of the bias voltage at the regime of [0.8 V, 1.0 V] while that should be forbidden when a negative bias voltage is applied, illustrating an interesting rectification effect, and the maximum rectification ratio is observed to be up to 57.85 and 55.85, respectively. The obtained NDR and rectification effect are physically explained from the integral of the transmission coefficient in the bias voltage window and the distribution of the real space charge density, and the demonstrated results are believed to be vital for the designing of the molecular switches, molecular rectifying devices and negative differential resistance devices based on benzoquinone molecules junction.