Systematic Control of Negative Transconductance in Organic Heterojunction Transistor for High‐Performance, Low‐Power Flexible Ternary Logic Circuits

Abstract

In this context, organic thin-film transistors (OTFTs) have been considered as one of the most promising building blocks for next-generation electronics owing to their light-weight, [4] large-area processability, [5] and inherent flexible nature. [6] With the numerous efforts in last two decades, OTFTs-based integrated circuits have been developed widely in low-end applications such as radio frequency identification (RFID) tags, [7] sensors, [8] and high-gain inverters for amplifiers. [9,10] However, further enhancement toward large-scale integrated circuits have been challenging as lithography-based fine patterning have been limited due to the low stability of organic semiconductors against high temperatures and various solvents. [11] Multi-valued logic (MVL) can be an important approach to conquer this downscaling issue. The enhanced data processing efficiency based on additional logic states in the new computing system displays a significant potential for increasing the integration density. [12,13] For example, the interconnect lines can be reduced by nearly 45% in a ternary logic system compared to that in the conventional binary logic system. [14] Ternary logic devices can be implemented by employing heterojunction transistors (H-TRs). The H-TRs have p-and n-type semiconductors with a partial junction of each semiconductor in contact with only one of the source and drain. This results in a negative transconductance (NTC), which is represented as a "flipped V"-shaped transfer characteristic. [15,16] The biggest advantage of this approach is that an MVL circuit can be achieved by replacing a transistor with an H-TR in a conventional inverter circuit design. This enables three-state logic operation without increasing the required number of transistors of the conventional binary logic circuit. Several ternary logic inverters (T-inverters) based on H-TRs have been proposed using various new materials including transition metal dichalcogenides (TMDs), [17][18][19][20][21][22][23][24][25] graphene, [26,27] organic semiconductors, [28,29] and hybrid material combinations. [30][31][32] Notwithstanding the successful demonstration of T-inverters, the antiambipolar characteristics of H-TRs that display a substantially low on/off current ratio (I on /I off ) hindered the full-swing of the Organic multi-valued logic (MVL) circuits can substantially improve the data processing efficiency in highly advanced wearable electronics. Organic ternary logic circuits can be implemented by utilizing the negative transconductance (NTC) of heterojunction transistors (H-TRs). To achieve high-performance organic ternary logic circuits, the range of NTC in H-TRs must be optimized in advance to ensure the well-defined intermediate logic state in ternary logic inverters (T-inverters). Herein, a simple and efficient strategy, which enables the systematic control of the range and position of NTC in H-TRs is presented. Each thickness of p-/n-type semiconductor in H-TRs is adjusted to control the channel conductivity. Furthermore, asymmetric ...

Structures, Properties, and Device Applications for [1]Benzothieno[3,2‐b]Benzothiophene Derivatives

“…[183][184][185][186] Moreover, through material combinations, the types of heterojunctions are formed to realize certain functions. [187] Li et al combined C8-BTBT with amorphous indium-gallium-zinc oxide (a-IGZO) as organic-inorganic heterojunction to realize ambipolar devices. [188] The smooth and compacted a-IGZO thin film provided good conditions for growing C8-BTBT thin film.…”

Carrier‐Transport Mechanism in Organic Antiambipolar Transistors Unveiled by Operando Photoemission Electron Microscopy

“…We proposed using organic p-and n-type semiconductors as transistor channels due to the following advantages: high controllability of energy levels by external fields, mechanical flexibility, and facile processability of organic materials. [18][19][20][21][22][23][24][25][26][27][28] Thus far, we have achieved considerably high gate tunability of the drain currents in organic AATs. [18][19][20] The ratio of the peak-and off-drain currents reached four orders of magnitude.…”

High-performance multivalued logic circuits based on optically tunable antiambipolar transistors

“…Antiambipolar transistors (AATs) have received considerable attention in the last few years due to their unique transfer characteristics. [1][2][3][4][5][6][7][8][9] Depending on the material properties and device geometries, AATs can produce ''L'' shaped [1][2][3] or ''N'' shaped [4][5][6] transfer curves with one [1][2][3][4][5][6] or a few [7][8][9] negative differential transconductance (NDT) regions. These noteworthy transport properties enable us to implement multivalued logic circuits (MVLs), which can handle more than two logic states.…”

“…These noteworthy transport properties enable us to implement multivalued logic circuits (MVLs), which can handle more than two logic states. [4][5][6]8,[10][11][12][13][14] This MVL concept is expected to greatly reduce the chip area without downscaling individual components due to the increase in the information-processing capability and therefore, facilitates the development of low-power and highspeed integrated circuits. [15][16][17][18][19] A wide variety of twodimensional (2D) materials and organic semiconductors have already been investigated with a view to further improve the device performance of the AATs and MVLs.…”