A photo detector is an optoelectronic device that can identify optical signals and convert them into electrical signals. Examples of photodetectors include photodiodes, phototransistors and photoconductors.
While there are many different types of photodetectors with different mechanisms and structures, the demonstrative behavior can be abbreviated as a limited set: the output current of a photodiode changes from corrected to a fully switched-on state upon exposure, while the output current of a photoconductor or a phototransistor shifts from full off to full on.
From the point of view of signal change behavior, there should exist a new device that changes the output current from full off to rectified state, and it can play an important role in potential optoelectronic systems such as high-precision imaging, optical logic and data processing.
For example, light-directed rectification can avoid the crosstalk problem of photodetector arrays without the use of selectors, thereby further improving the integration of the array.
Dong-Ming Sun Group of the Institute of Metal Research, Chinese Academy of Sciences recently proposed a new device called a photon controlled diode, which can change the output current from a completely turned off state to a corrected state after lighting for the very first time. , resulting in an anti-crosstalk photo memory array without the use of selectors. The newspaper is published in National Scientific Review†
Researchers use lateral n/n molybdenum disulfide (MoS2) junction as a channel, graphene as contact electrodes and hexagonal boron nitride (h-BN) as a photogate layer material to fabricate the photon-driven diode, which is an n/n Moss2 junction implanted between two graphene/MoS2 Schottky junctions at the cathode and anode.
Organized by light, the Schottky nodes beat or make the rectification performance of the n/n. possible junction so that the output current of the photon controlled diode can change from fully off to rectified state.
The light-to-dark rectification ratio can reach more than 106. Its responsiveness as a photo detector is greater than 105 A/W as the thickness of the photohole layer is increased, the behavior of the device shifts to a multi-function photo memory with the largest non-volatile resonance of 4.8 × 107 A/W and the longest retention time of 6.5 × 106 seconds reported so far.
Using the photon driven diodes as pixel units, a 3×3 photo memory array is fabricated without consuming selectors, without crosstalk and functions of wavelength and power density selectivity. This research paves the way for the development of new, high integration, low power and smart optoelectronic systems.
The National Natural Science Foundation of China funded this research.
Feng, S., et al† (2022) A photon-driven diode with novel signal processing behavior. National Scientific Review† doi.org/10.1093/nsr/nwac088†