High-performance visible to near-infrared photodetectors by using (Cd,Zn)Te single crystal

The authors report on a high-performance metal-semiconductor-metal (MSM) photodetector fabricated on the Cd_0.96Zn_0.04Te single crystal with the photoresponse from visible to near infrared region. Benefitting from the high-quality single crystallization, an ultra-low dark current of ~10^-10 A was obtained at a high applied voltage of 10 V, leading to a photo-to-dark-current ratio of more than 10³ at 700 nm light illumination. The highest responsivity is estimated to be 1.43 A/W with a specific detectivity of 3.31 × 10¹² Jones at 10 V at a relatively lower injection power density. The discrimination ratio between the near infrared region of 800 nm and 900 nm is almost 10², which is high enough for the accurate spectra selectivity. The MSM photodetector also exhibits a fast response speed of ~800 μs and extremely low persistent photoconductivity (PPC), while the PPC is inhibited at high temperatures.