High signal/noise ratio deep UV detector with maximum response at 230 nm based on mix-phase MgZnO deposited under high laser energy condition. (8th November 2018)

• Record Type: Journal Article
• Authors: Han, S.; Hu, S. R.; Cao, P. J.; Liu, W. J.; Zeng, Y. X.; Jia, F.; Xu, W. Y.; Liu, X. K.; Zhu, D. L.; Lu, Y. M.
• Is Part Of: Europhysics letters. Volume 124:Number 1(2018:Oct.)
• Publication Date: 2018-11-08
• Subjects: 85.60.Gz -- 85.60.-q -- 73.61.Jc; Physics -- Periodicals; Electronic journals; 530.05
• DOI: 10.1209/0295-5075/124/18006
• Languages: English
• ISSNs: 0295-5075

Abstract

Abstract: A Mix-phase MgZnO thin film was fabricated on the c -plane sapphire substrate (Mg0.4 Zn0.6 O target) under high laser energy density condition by the PLD method. The internal quantum efficiency of the detector based on the mix-phase MgZnO thin film at 230 nm deep UV light reached 86% at 40 V bias voltage. And the I uv (230 nm)/ I dark ratio of the MgZnO detector reached 864 at 40 V bias voltage, which is mainly caused by both the higher internal gain of the detector at deep UV light and its smaller I dark . The high internal gain of the detector is mainly due to the higher density of interfaces between the different structure of MgZnO grains in the mix-phase MgZnO thin film, which is caused by the higher laser energy density deposition condition certified by contrast experiments. The small I dark of the detector is mainly caused by the higher barriers in the mix-phase MgZnO thin film and more cubic MgZnO in the mix-phase MgZnO thin film, and higher laser energy density deposition condition and O-rich c -plane sapphire substrate surface are key factors, which also agree with the contrast experiments results. So when the mix-phase MgZnO thin film that is constituted by both a small number of narrower band gap hexagonal MgZnO and a large number of wide band gap cubic MgZnO is used in the deep UV detector, and the difference in band gaps between different structures of MgZnO is relatively higher, a higher signal/noise ratio of the device at 230 nm deep UV light is gained, which is meaningful for developing high-performance deep UV detection technology.