[paper] Bioinspired Phototransistor

Ruyue Han, Dayu Jia, Bo Li, Shun Feng, Guoteng Zhang, Yun Sun, Zheng Han, Chi Liu, Hui-Ming Cheng and Dong-Ming Sun

Bioinspired phototransistor with tunable sensitivity for low-contrast target detection

Light Sci Appl 15, 12 (2026) DOI: 10.1038/s41377-025-02051-1

Shenyang National Laboratory for Materials Science, Institute of Metal Research, CAS, Shenyang (CN)
School of Materials Science and Engineering, University of Science and Technology of China, Shenyang (CN)
School of Information Institution, Liaoning University, Shenyang (CN)
State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan (CN)
Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan (CN)
Liaoning Academy of Materials, Shenyang (CN)
Faculty of Materials Science and Engineering, Shenzhen Institute of Advanced Technology, CAS, Shenzhen (CN)

Abstract: Accurate recognition of low-contrast targets in complex visual environments is essential for advanced intelligent machine vision systems. Conventional photodetectors often suffer from a weak photoresponse and a linear dependence of photocurrent on light intensity, which restricts their ability to capture low-contrast features and makes them susceptible to noise. Inspired by the adaptive mechanisms of the human visual system, we present a molybdenum disulfide (MoS2) phototransistor with tunable sensitivity, in which the gate stack incorporates a heterostructure diode—composed of O-plasma-treated MoS2 and pristine MoS2—that serves as the photosensitive layer. This configuration enables light-intensity-dependent modulation of the diode’s conductance, which dynamically in turn alters the voltage distribution across the gate dielectric and transistor channel, leading to a significant photoresponse. By modulating the gate voltage, the light response range can be finely tuned, maintaining high sensitivity to low-contrast targets while suppressing noise interference. Compared to conventional photodetectors, the proposed device achieves a 1000-fold improvement in sensitivity for low-contrast signal detection and exhibits significantly enhanced noise immunity. The intelligent machine vision system built on this device demonstrates exceptional performance in detecting low-contrast targets, underscoring its promise for next-generation machine vision applications.

FIG: Performance of tunable-sensitivity phototransistor array. (a) Optical image of a 3 × 3 phototransistor array (scale bar: 200 μm). (b) Magnified image of an individual sensor unit (scale bar: 10 μm). 

(c) IDS−VGS curves of the 9 phototransistors in dark and under 516-nm light at VDS = 0.1 V. 

Acknowledgements: This work was supported by the National Key Research and Development Program of China (2021YFA1200801), the National Natural Science Foundation of China (No. 62304226, 52188101, 62450124, 62125406), the China Postdoctoral Science Foundation (2024T170946, 2023M733574), the Excellent Youth Fund Project of Liaoning Province (2023JH3/10200003), the Outstanding Youth Fund Project of Liaoning Province (2025JH6/101100015), the Special Projects of the Central Government in Guidance of Local Science and Technology Development (2024010859-JH6/1006), the Special Research Assistantship Project of the Chinese Academy of Sciences (E455L502), the China Postdoctoral Science Foundation under Grant Number GZB20230776, the Liaoning Provincial Key Laboratory of Public Opinion and Network Security Information System (d252453002), the Artificial Intelligence Technology Innovation Project of Liaoning Province (Grant No. 2023JH26/10300019), the Young Top-notch Talents of the National High-level Talent Special Support Program, the basic scientific research project of universities funded by the Liaoning Provincial Department of Education (LJ212510140016) and the Liaoning Province High-quality Industry-University Cooperation and Collaborative Education Project (241201160090747). The authors gratefully acknowledge Dr. Bing Yang and Dr. Honglei Chen from the Institute of Metal Research for their valuable support in HRTEM-EDS characterization.

[thesis] SPICE modeling of light and radiation effects in ICs

A novel approach for SPICE modeling of light and radiation effects in ICs

Chiara ROSSI

Présentée le 29 janvier 2021

à la Faculté des sciences et techniques de l’ingénieur Groupe de scientifiques IEL

Programme doctoral en microsystèmes et microélectronique

pour l’obtention du grade de Docteur ès Sciences

DOI:10.5075/epfl-thesis-8422

Modeling the interaction of ionizing radiation, either light or ions, in integrated circuits is essential for the development and optimization of optoelectronic devices and of radiation-tolerant circuits. Whereas for optical sensors photogenerated carriers play an essential role, high energy ionizing particles can be a severe issue for circuits, as they create high density of excess carriers in ICs substrate, causing parasitic signals. In particular, recent advances in CMOS scaling have made circuits more sensitive to errors and dysfunctions caused by radiation-induced currents, even at the ground level. TCAD simulations of excess carriers generated by light or radiation are not dedicated to large scale circuit simulations since only few devices can be simulated at a time and computation times are too long. Conversely, SPICE simulations are faster, but their accuracy is strictly dependent on the correctness of the compact models used to describe the devices, especially when dealing with photocurrents and parasitic radiation-induced currents.

The objective of this thesis is to develop a novel modeling approach for SPICE compatible simulations of electron-hole pairs generated by light and by high energy particles. The approach proposed in this work is based on the Generalized Lumped Devices, previously developed to simulate parasitic signals in High Voltage MOSFET ICs. Here, the model is extended to include excess carriers generation. The developed approach allows physics-based simulations of semiconductor structures, hit by light or radiation, that can be run in standard circuit simulators without the need for any empirical parameter, only relying on the technological and geometrical parameters of the structure, and without any predefined compact model. The model is based on a coarse mesh of the device to obtain an equivalent network of Generalized Lumped Devices. The latter predicts generation of excess carriers and their propagation, recombination and collection at circuit nodes through the definition of equivalent voltages, proportional to the excess carrier concentrations, and equivalent currents, proportional to the excess carrier gradients. The model is validated with commercial TCAD numerical simulations for different scenarios. Regarding light effects, the proposed strategy is applied to simulate various optoelectronic devices. Complete DC I-V characteristics of a solar cell and transient response of a photodiode are studied. Next, phototransistors are considered. After, a full pixel of a 3T-APS CMOS image sensor is analyzed. The photosensing device, described with Generalized Devices, is co-simulated with the in-pixel circuit, described with compact models. The impact of semiconductor parameters on pixel output and on crosstalk between adjacent pixels is predicted. Finally, radiation-induced soft errors in ICs are examined. Alpha particles at different energies hitting the substrate are simulated. Parasitic currents collected at contacts are studied as a function of particles position and energy. Funneling effect, which is a phenomenon specific to high injection, is also included in the model.

This work shows that the Generalized Lumped Devices approach can be successfully used for SPICE simulations of optoelectronic devices and for prediction of radiationinduced parasitic currents in ICs substrate. This thesis is a first step towards a complete and flexible tool for excess carriers modeling in standard circuit simulators.

Fig: Layout, mesh (gray dashed lines) and equivalent network of Generalized Lumped Devices (Generalized Homojunctions, Resistors and Diodes). The structure is uniformly illuminated from the left side, justifying a 1D discretization scheme.