Multi-terminal memtransistors from polycrystalline monolayer molybdenum disulfide
Polycrystalline monolayer molybdenum disulfide is used to fabricate a multi-terminal device combining a memristor and a transistor, which can mimic biological neurons with multiple synapses for neuromorphic computing applications. Memtransistor mimics multiple synapses Memristors are two-terminal de...
Saved in:
Published in | Nature (London) Vol. 554; no. 7693; pp. 500 - 504 |
---|---|
Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
22.02.2018
Nature Publishing Group |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Polycrystalline monolayer molybdenum disulfide is used to fabricate a multi-terminal device combining a memristor and a transistor, which can mimic biological neurons with multiple synapses for neuromorphic computing applications.
Memtransistor mimics multiple synapses
Memristors are two-terminal devices whose resistance exhibits a memory effect that depends on the current or voltage history. This memory enables such devices to mimic the behaviour of a neural synapse, making them of great interest for creating brain-inspired neuromorphic computing architectures. Basic neural functions have been demonstrated with two-terminal devices, but more complex functions, such as heterosynaptic plasticity, will probably require devices with multiple terminals. Mark Hersam and colleagues combine the restive switching behaviour of a memristor with the gate-tunability of a transistor into one multi-terminal device called a memtransistor. Based on two-dimensional layers of molybdenum disulfide, such memtransistors not only exhibit conventional neural learning behaviour but also heterosynaptic functionality, providing a platform for mimicking biological neurons with multiple synapses.
Memristors are two-terminal passive circuit elements that have been developed for use in non-volatile resistive random-access memory and may also be useful in neuromorphic computing
1
,
2
,
3
,
4
,
5
,
6
. Memristors have higher endurance and faster read/write times than flash memory
4
,
7
,
8
and can provide multi-bit data storage. However, although two-terminal memristors have demonstrated capacity for basic neural functions, synapses in the human brain outnumber neurons by more than a thousandfold, which implies that multi-terminal memristors are needed to perform complex functions such as heterosynaptic plasticity
3
,
9
,
10
,
11
,
12
,
13
. Previous attempts to move beyond two-terminal memristors, such as the three-terminal Widrow–Hoff memristor
14
and field-effect transistors with nanoionic gates
15
or floating gates
16
, did not achieve memristive switching in the transistor
17
. Here we report the experimental realization of a multi-terminal hybrid memristor and transistor (that is, a memtransistor) using polycrystalline monolayer molybdenum disulfide (MoS
2
) in a scalable fabrication process. The two-dimensional MoS
2
memtransistors show gate tunability in individual resistance states by four orders of magnitude, as well as large switching ratios, high cycling endurance and long-term retention of states. In addition to conventional neural learning behaviour of long-term potentiation/depression, six-terminal MoS
2
memtransistors have gate-tunable heterosynaptic functionality, which is not achievable using two-terminal memristors. For example, the conductance between a pair of floating electrodes (pre- and post-synaptic neurons) is varied by a factor of about ten by applying voltage pulses to modulatory terminals.
In situ
scanning probe microscopy, cryogenic charge transport measurements and device modelling reveal that the bias-induced motion of MoS
2
defects drives resistive switching by dynamically varying Schottky barrier heights. Overall, the seamless integration of a memristor and transistor into one multi-terminal device could enable complex neuromorphic learning and the study of the physics of defect kinetics in two-dimensional materials
18
,
19
,
20
,
21
,
22
. |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0028-0836 1476-4687 |
DOI: | 10.1038/nature25747 |