Broadband Optoelectronic Synaptic Thin‐Film Transistors Based on Oxide Semiconductors. Issue 4 (14th January 2020)

• Record Type: Journal Article
• Authors: Duan, Hongxiao; Javaid, Kashif; Liang, Lingyan; Huang, Lu; Yu, Jiahuan; Zhang, Hongliang; Gao, Junhua; Zhuge, Fei; Chang, Ting-Chang; Cao, Hongtao
• Is Part Of: Physica status solidi. Volume 14:Issue 4(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-01-14
• Subjects: artificial neural networks -- biological synaptic behaviors -- effective electron mass -- persistent photoconductivity -- transparent oxide semiconductors; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.201900630
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : Optoelectronic synapse, well coupling the optical and electrical signals in one device, is an important building block in neuromorphic hardware library. Herein, optoelectronic synaptic devices are demonstrated based on a unique amorphous oxide semiconductor (InGaCdO [IGCO]) that can be spiked by broadband light signals from ultraviolet to near‐infrared region, approaching the wavelength of 1000 nm. These optically stimulated synaptic devices are based on the conventional bottom‐gate thin‐film transistor (TFT) configuration, providing the beneficial process/structural compatibility with the flat‐panel display industry. The IGCO TFTs, showing an ultrahigh field‐effect mobility up to 106 cm 2 V −1 s −1, can well simulate a series of basic synaptic functionalities via changing the pulse intensity, number, and frequency. The device plasticity originates from the dynamic ionization and neutralization of oxygen vacancy‐related defects. Also, the mechanism underlying this dynamic process is discussed in detail, verifying that oxygen vacancy can turn to its ionized state by directly absorbing a photon having enough energy or with the aid of holes. The relatively higher carrier mobility, smaller bandgap, and larger activation energy of oxygen vacancy for the IGCO together facilitate the achievement of broadband optoelectronic synaptic devices. Abstract : Bottom‐gate staggered thin‐film transistors are fabricated using magnetron‐sputtering amorphous InGaCdO (IGCO) semiconductor, showing ultrahigh field‐effect mobility up to 106 cm 2 V −1 s −1, smaller bandgap, and larger activation energy compared with the well‐studied InGaZnO counterpart. Also, the IGCO TFT synapses behave in a neuron‐like fashion under the ultraviolet to near‐infrared light stimuli, which is clarified by the ionization model of oxygen vacancy.