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North Institute of Technology has made new progress in the dark current suppression technology of infrared photodetectors.
Release time：2023-12-14
Infrared photodetectors are widely used in gas sensing, meteorological remote sensing and space exploration. However, at present, traditional infrared detection materials are mainly based on indium telluride, indium gallium arsenic, mercury cadmium telluride, etc., which need to be grown by molecular beam epitaxy, and complex processes such as flip-chip bonding and coupling with readout circuits. Although the detection performance is high, it is limited by cost and yield.
InfraredPhotodetectorWidely used in gas sensing, meteorological remote sensing and space exploration and other fields. However, at present, traditional infrared detection materials are mainly based on indium telluride, indium gallium arsenic, mercury cadmium telluride, etc., which need to be grown by molecular beam epitaxy, and complex processes such as flip-chip bonding and coupling with readout circuits. Although the detection performance is high, it is limited by cost and yield.
Colloidal quantum dots (CQD), as an emerging infrared detection material, can be synthesized on a large scale by chemical thermal injection, and "ink-type" liquid phase processing can be directly coupled with silicon readout circuits, greatly accelerating the development of infrared focal plane arrays (FPA). At present, Professor Hao Qun's team of Beijing University of Technology has realized 320 × 256 and 1K × 1K megapixel quantum dot infrared focal planes. However, the large dark current noise of infrared colloidal quantum dots limits the resolution and sensitivity of the imager.
Recently, the research team of Beijing University of Technology proposed a quantum dot band tail control method. Through the re-growth technology of quantum dot nucleation and growth separation, the morphology was successfully controlled (as shown in the figure1) infrared quantum dots with good dispersion, narrow half peak width and excellent band tail state.
Figure1 Schematic diagram of quantum dot morphology synthesized by different precursors
The researchers prepared a single-pixel photoconductive detector based on three colloidal quantum dots, which greatly reduced the dark current and noise of the device.More than 30 times, the detection rate of 2.5 μm extended short wave band at room temperature reaches 4 × 10 ¹ Jones, and the response time is 0.94 μs (as shown in fig. 2).
Figure2 Schematic diagram of the structure of the photoconductive detector and the device performance comparison of the shape-controlled quantum dots with two sets of reference samples.
On this basis, the researchers willHgTe colloidal quantum dots are integrated with complementary metal oxide semiconductor (CMOS) readout integrated circuit (ROIC) to fabricate a focal plane array imaging chip with 640 × 512 pixels, and the effective pixel rate is as high as 99.997%. The schematic diagram of the imaging process and the imaging results are shown in Figure 3.
Figure3 Schematic diagram of imaging process and focal plane imaging results of shape-controlled quantum dots 640 × 512 pixels
In summary, this study developed a quantum dot band tail control method, through a single pixelPhotodetectorand infrared focal plane to verify the reliability of the method in dark current and noise suppression, in high-performance colloidal quantum dot infraredlight detectordevelopment is of great significance.
related research work inIn November 2023, it was published in ACS Photonics, the top optical journal of Chinese Academy of Sciences, Zone 1. The co-first authors of the paper are Professor Hao Qun, PhD students Xue Xiaomeng and Luo Yuning, and the corresponding authors are Professor Chen Menglu and Professor Tang Xin.
Thesis Link: https://www.instrument.com.cn/news/20231117/692581.shtml
Source: infrared core smell
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