High performance photodetectors are widely used in optical imaging and sensing, environmental monitoring, chemical/biological sensing and other fields, which are of great significance in the military and civilian fields. With the continuous expansion of the application field in recent years, the performance of photoelectric detectors and demand for multi-band detection have increased. Among them, the III-V semiconductor materials represented by GaAs nanowires have been widely studied in the field of photoelectric detection due to their high electron mobility and photoelectric conversion efficiency. Constructing photodetectors with GaAs nanowires is conducive to achieving high-performance multi band detection.

However, there are still some problems in the research based on GaAs nanowire photodetectors. The large surface defects of the nanowire surface due to the inherent large specific surface area of the one-dimensional nanowires lead to the capture of carriers, and the fixed electronic energy band limits its absorption range, resulting in the limited response band and performance of GaAs based nanostructure photodetectors. In order to solve the above problems, Professor Zhipeng Wei team proposed to the heterogeneous combination of perovskite materials with high absorption coefficients with GaAs nanowire materials to construct hybrid dimensional high-performance photodetectors. By using perovskite materials to enhance the optical response of photodetectors, the Type-II band structure constructed by heterojunction of perovskite and GaAs nanowires can also promote carrier separation, increase the concentration of hole carriers in the nanowires, and ultimately achieve high-performance multi band detection. This study provides an effective method for the combination of multidimensional materials. Perovskite/GaAs nanowire hybrid photodetectors have broad application prospects in fields such as optical communication, digital imaging, and nighttime monitoring. The relevant research results were published in Photonics Research, Volume 11, No. 4, 2023 ( Xiaobing Hou, Xitong Hong, Fengyuan Lin, Jinzhi Cui, Qian Dai, Qianlei Tian, Bingheng Meng, Yanjun Liu, Jilong Tang, Kexue Li, Lei Liao, Zhipeng Wei. Perovskite/GaAs-nanowire hybrid structure photodetectors with ultrafast multiband response enhancement by band engineering[J]. Photonics Research, 2023, 11(4): 541).

As shown in Figure 1, the photoelectric detection of P-type GaAs nanowires is mainly based on hole carriers. Through the heterojunction of designed band matching perovskite material, a Type-II band structure is constructed to promote carrier separation, effectively increase hole concentration in the nanowires, improve photocurrent and response time. In addition, perovskite is covered on the surface of the nanowire, improving the light response ability of a single nanowire photodetector, reducing surface defects of the nanowire, suppressing dark current, and ultimately achieving performance improvements in various detection parameters such as photodetector responsivity, detectivity, and response time in the ultraviolet and visible light bands.

Fig.1 The energy band structure diagram and detection performance comparison of single GaAs nanowires and heterostructure photodetectors.

At present, the performance of hybrid dimensional heterostructure photodetector has been improved in all aspects, which has certain advantages over traditional detection. The team will subsequently conduct research on infrared band detection, further improve the detection performance of the photodetector, and achieve ultraviolet-visible-infrared multi-band detection.