| LI Gang,FU Zheng-wei,SONG Yan-dong,MA Zong-yi,LIU Zi-tong,FENG Li-zhi,FENG Si-yu.Photoelectric Properties of p-GaN/ZnO Nanowires/ZnO Thin Film Sandwich Heterojunction Ultraviolet Photodetector[J],52(6):384-391 |
| Photoelectric Properties of p-GaN/ZnO Nanowires/ZnO Thin Film Sandwich Heterojunction Ultraviolet Photodetector |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.06.035 |
| KeyWord:heterojunction photodetector CVD responsivity specific detectivity external quantum efficiency |
| Author | Institution |
| LI Gang |
School of Materials Science and Engineering, Liaoning Technical University, Liaoning Fuxin , China;School of Materials Science and Engineering, Yingkou Institute of Technology, Liaoning Yingkou , China |
| FU Zheng-wei |
School of Materials Science and Engineering, Liaoning Technical University, Liaoning Fuxin , China;Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
| SONG Yan-dong |
School of Materials Science and Engineering, Liaoning Technical University, Liaoning Fuxin , China;Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
| MA Zong-yi |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
| LIU Zi-tong |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
| FENG Li-zhi |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
| FENG Si-yu |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang , China |
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| Abstract: |
| The photodetector is a device that converts an optical signal into an electrical one. In our daily life, high-performance photodetectors play an important role in many fields, including photoelectric display, imaging, environmental monitoring, optical communication, military, security inspection, and etc. It is a critical component in the modern miniaturized electronic industry. The work aims to design a novel p-GaN/ZnO (thin film+nanowire) sandwich heterojunction structure to improve the response of ZnO to ultraviolet light. The sandwich structure of ZnO nanowire (NWS) and nanosheet was grown by chemical vapor deposition (CVD) in a single-temperature zone high-temperature tubular furnace, and its growth temperature was 1 050 ℃, holding time was 25 min, and with 30 mL/min argon protection. First of all, spin Ag NWS on the surface of ZnO thin film with the spin-coating method uniformly. Secondly, dilute hydrochloric acid was used to erase the ZnO structure on the GaN substrate as the attachment point of the silver glue. At the same time, a drop of silver gel on the Ag NWS was used as another attachment point, then the process of UV photodetector based on p-GaN/ZnO heterojunction was completed. The advantage of the electrode preparation process of this device was that it could avoid tedious steps such as light carvings. X-ray diffractometer (XRD) and scanning electron microscope (SEM) were used to characterize the phase and morphology and the law of photoelectric performance. The changes of sandwich heterojunction UV photodetector were tested with a semiconductor analyzer. The results indicated that the sandwich structure sample was interlaced with ZnO NWS and ZnO nanosheets inside, and its surface was ZnO thin film and relatively smooth. ZnO was single crystal with good crystal quality. The photodetector had obvious rectifier characteristics, at 2 V bias voltage, 520 μW/cm2 optical power density (365 nm), the responsivity (R) was 35.8 A/W, the rise time (tr) was 41.83 ms, the descending time (td) was 43.21 ms, the external quantum efficiency (Eq) was 122%, and the specific detection rate (D) was 1.31×1012 cm.Hz1/2.W−1. The optical response enhancement mechanism of this experiment was:under the condition of 365 nm ultraviolet light, on the one hand, part of the light would be absorbed by the top ZnO film, and some light would enter the ZnO nano-sliced and ZnO NWS area through the ZnO film. In this field, reflection, scattering, and absorption occurred repeatedly. On the other hand, although a large part of the light was reflected and absorbed by ZnO, it still reached GaN at the bottom. Therefore, the incident light will reflect and absorb multiple times within the entire sandwich structure, which means the length of the light will be longer, and enhance the absorption of the materials for the light, resulting in the density of pairs of electrons and holes inside ZnO and GaN materials increased significantly. Under the influence of the construction of the electric field, the separation efficiency of pairs of electrons and holes is enhanced a lot, and Ag electrodes increase the efficiency of electrons and enhance light response. |
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