{"title":"Ultra-highly linear Ga2O3-based cascade heterojunctions optoelectronic synapse with thousands of conductance states for neuromorphic visual system.","authors":"Peng Li,Xuanyu Shan,Ya Lin,Yi Du,Jiangang Ma,Zhongqiang Wang,Xiaoning Zhao,Ye Tao,Haiyang Xu,Yichun Liu","doi":"10.1038/s41377-025-01897-9","DOIUrl":null,"url":null,"abstract":"Ultrawide bandgap semiconductor optoelectronic synapses can perform high-parallel computing with a low false alarm rate, making them ideal for building deep-ultraviolet (DUV) neuromorphic visual system (NVS). However, the rapid carrier recombination in these optoelectronic synapses results in a poor number of conductance states and a low linear weight update protocol, consequently degrading the image recognition accuracy of DUV NVSs. This work proposes a type of cascade heterojunctions capable of finely tuning the dynamics of photogenerated carriers, utilizing aluminum interdigital electrodes sandwiched between tin-doped Ga2O3 and oxygen-deficient hafnium oxide (GTO/Al/HfOx) films. The built-in fields at the GTO/HfOx heterojunction and the Al/HfOx hole Schottky junction interfaces facilitate the separation of photogenerated carriers and the subsequent trapping of holes by the oxygen defects in the HfOx, respectively. The GTO/Al/HfOx optoelectronic synapses exhibit an ultrahigh responsivity of over 104 A/W and a large photo-to-dark current ratio of 6 × 105, which results in exceptional synaptic plasticity with unprecedented 4096 conductance states and excellent linearity with a fitting coefficient of 0.992. These attributes enable the GTO/Al/HfOx optoelectronic synapses to execute logical operations with fault-tolerance capability and to achieve high-accuracy fingerprint classification. The innovative cascade heterojunctions design, along with the elucidated carrier dynamics modulation mechanism, facilitates the development of DUV NVSs.","PeriodicalId":18069,"journal":{"name":"Light-Science & Applications","volume":"99 1","pages":"354"},"PeriodicalIF":23.4000,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Light-Science & Applications","FirstCategoryId":"1089","ListUrlMain":"https://doi.org/10.1038/s41377-025-01897-9","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"OPTICS","Score":null,"Total":0}
引用次数: 0
Abstract
Ultrawide bandgap semiconductor optoelectronic synapses can perform high-parallel computing with a low false alarm rate, making them ideal for building deep-ultraviolet (DUV) neuromorphic visual system (NVS). However, the rapid carrier recombination in these optoelectronic synapses results in a poor number of conductance states and a low linear weight update protocol, consequently degrading the image recognition accuracy of DUV NVSs. This work proposes a type of cascade heterojunctions capable of finely tuning the dynamics of photogenerated carriers, utilizing aluminum interdigital electrodes sandwiched between tin-doped Ga2O3 and oxygen-deficient hafnium oxide (GTO/Al/HfOx) films. The built-in fields at the GTO/HfOx heterojunction and the Al/HfOx hole Schottky junction interfaces facilitate the separation of photogenerated carriers and the subsequent trapping of holes by the oxygen defects in the HfOx, respectively. The GTO/Al/HfOx optoelectronic synapses exhibit an ultrahigh responsivity of over 104 A/W and a large photo-to-dark current ratio of 6 × 105, which results in exceptional synaptic plasticity with unprecedented 4096 conductance states and excellent linearity with a fitting coefficient of 0.992. These attributes enable the GTO/Al/HfOx optoelectronic synapses to execute logical operations with fault-tolerance capability and to achieve high-accuracy fingerprint classification. The innovative cascade heterojunctions design, along with the elucidated carrier dynamics modulation mechanism, facilitates the development of DUV NVSs.