An Ultralow Power Mixed Dimensional Heterojunction Transistor Based on the Charge Plasma pn Junction

Abstract

terms of switching performance when its thickness approaches atomic thickness. [3] Besides of its atomic thickness, TMDCs have no dangling or broken bonds on their surfaces, which gives another advantage over silicon by suppressing scattering of the charge carriers from the surfaces.However, TMDCs have major issues hindering its adoption in microelectronics to replace the silicon; one is the reduction of the contact resistance, and the other one is the modulation of doping. Formation of Schottky barrier between a contacting metal and a TMDC is known from the early stage of the TMDC research. [4] Ohmic contacts have been demonstrated by several methods, such as insertion of graphene between the metal and TMDC, [5] or use of a specific metal, like Bi. [6] Thus there has been progress toward realizing the ohmic contact on the TMDC. The most intensively researched TMDC materials, such as MoS 2 , WS 2 , HfS 2 , HfSe 2 are electron-doped (n-doped or n-type) materials due to the sulfur vacancies, [7] and MoSe 2 , MoTe 2 , WSe 2 are ambivalent. [4] There are lots of on-going efforts to find a stable and reliable hole-doping (p-doped or p-type) method for the above materials, [8] albeit the number of reports on the p-doping is still relatively smaller than that of the n-doping. Representatively, there are three groups of method, charge Development of a reliable doping method for 2D materials is a key issue to adopt the materials in the future microelectronic circuits and to replace the silicon, keeping the Moore's law toward the sub-10 nm channel length. Especially hole doping is highly required, because most of the transition metal dichalcogenides (TMDC) among the 2D materials are electron-doped by sulfur vacancies in their atomic structures. Here, hole doping of a TMDC, tungsten disulfide (WS 2 ) using the silicon substrate as the dopant medium is demonstrated. An ultralow-power current sourcing transistor or a gated WS 2 pn diode is fabricated based on a charge plasma pn heterojunction formed between the WS 2 thin-film and heavily doped bulk silicon. An ultralow switchable output current down to 0.01 nA µm −1 , an off-state current of ≈1 × 10 −14 A µm −1 , a static power consumption range of 1 fW µm −1 -1 pW µm −1 , and an output current ratio of 10 3 at 0.1 V supply voltage are achieved. The charge plasma heterojunction allows a stable (less than 3% variation) output current regardless of the gate voltage once it is turned on.

Microelectronic current-sourcing device based on band-to-band tunneling current

“…In our device, a tunneling barrier is formed by the facile transfer of a two-dimensional material, tungsten disulfide (WS 2 ), on top of heavily hole-doped bulk silicon (p ++ -Si), forming a mixed-dimensional heterojunction. As demonstrated in a previous study, because the socalled pinned junction exists at the heterojunction [6], the drain-source bias has a limited field effect on the thickness modulation of the tunneling barrier between the two materials, resulting in a saturated drain current. However, the magnitude of the output current is modulated exponentially using the gate potential in the range below 10 -10 A μm −1 .…”

“…Switchable single microelectronic devices producing a constant current are rare [6]. However, circuits exist for constant-current sourcing.…”

Synaptic and Gradual Conductance Switching Behaviors in CeO2/Nb–SrTiO3 Heterojunction Memristors for Electrocardiogram Signal Recognition

“…Kim et al obtained a high recognition rate of 93% for handwritten numerals in the TiN/TaO 2 /Pt device through adjusting the Schottky barrier height by the oxygen migration between electrodes and TaO 2. Nevertheless, the current transmission in the Schottky barrier-based metal–semiconductor memristors has no relaxation process, which is not conducive to simulating long-term plasticity of neural synapses. , In contrast, the separation and recombination of carriers in the Schottky barrier-based oxide-semiconductor heterojunction take some time. , On the other hand, CeO 2 memristors are widely studied because of their excellent characteristics such as a high ON/OFF ratio and high stability. − However, we hardly see studies on the application of CeO 2 devices in artificial synapses, which may be due to their abrupt conductance change. This disadvantage could be overcome by replacing the metal electrode with a doped semiconductor such as Nb–SrTiO 3 because the gradual conductance change could be achieved by charge trapping/detrapping at the CeO 2 film and the Nb–SrTiO 3 heterojunction …”

“…2,21 In contrast, the separation and recombination of carriers in the Schottky barrier-based oxidesemiconductor heterojunction take some time. 22,23 On the other hand, CeO 2 memristors are widely studied because of their excellent characteristics such as a high ON/OFF ratio and high stability. 24−26 However, we hardly see studies on the application of CeO 2 devices in artificial synapses, which may be due to their abrupt conductance change.…”

Engineered Bio‐Heterojunction with Infection‐Primed H2S Liberation for Boosted Angiogenesis and Infectious Cutaneous Regeneration

“…[41] Interestingly, introduction of the n-type semiconductors like bismuth sulfide (Bi 2 S 3 ), [42][43][44][45][46] can effectively separate these electrons and holes via the powerful self-built-in electric fields generated at the interface between n-type and p-type semiconductors. [47] Thus, the designed P-N bio-heterojunction (bio-HJ) materials (Bi 2 S 3 @CuS, abbreviated as BC) are capable of achieving higher catalytic efficiency than CuS alone. Notably, the inherent electric field has also been found to exert positive effects in many physiological processes, such as embryonic development, cell proliferation, and tissue reconstruction.…”