Tan Chaoliang, Amani Matin, Zhao Chunsong, Hettick Mark, Song Xiaohui, Lien Der-Hsien, Li Hao, Yeh Matthew, Shrestha Vivek Raj, Crozier Kenneth B, Scott Mary C, Javey Ali
Electrical Engineering and Computer Sciences, University of California at Berkeley, Berkeley, CA, 94720, USA.
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
Adv Mater. 2020 Sep;32(38):e2001329. doi: 10.1002/adma.202001329. Epub 2020 Aug 9.
Semiconducting absorbers in high-performance short-wave infrared (SWIR) photodetectors and imaging sensor arrays are dominated by single-crystalline germanium and III-V semiconductors. However, these materials require complex growth and device fabrication procedures. Here, thermally evaporated Se Te alloy thin films with tunable bandgaps for the fabrication of high-performance SWIR photodetectors are reported. From absorption measurements, it is shown that the bandgaps of Se Te films can be tuned continuously from 0.31 eV (Te) to 1.87 eV (Se). Owing to their tunable bandgaps, the peak responsivity position and photoresponse edge of Se Te film-based photoconductors can be tuned in the SWIR regime. By using an optical cavity substrate consisting of Au/Al O to enhance its absorption near the bandgap edge, the Se Te film (an optical bandgap of ≈0.8 eV)-based photoconductor exhibits a cut-off wavelength at ≈1.7 μm and gives a responsivity of 1.5 AW and implied detectivity of 6.5 × 10 cm Hz W at 1.55 μm at room temperature. Importantly, the nature of the thermal evaporation process enables the fabrication of Se Te -based 42 × 42 focal plane arrays with good pixel uniformity, demonstrating the potential of this unique material system used for infrared imaging sensor systems.
高性能短波红外（SWIR）光电探测器和成像传感器阵列中的半导体吸收体主要由单晶硅锗和III-V族半导体主导。然而，这些材料需要复杂的生长和器件制造工艺。在此，报道了用于制造高性能SWIR光电探测器的具有可调带隙的热蒸发硒化碲合金薄膜。通过吸收测量表明，硒化碲薄膜的带隙可以从0.31电子伏特（碲）连续调谐到1.87电子伏特（硒）。由于其可调带隙，基于硒化碲薄膜的光电导体的峰值响应位置和光响应边缘可以在SWIR范围内进行调谐。通过使用由金/氧化铝组成的光学腔衬底来增强其在带隙边缘附近的吸收，基于硒化碲薄膜（光学带隙约为0.8电子伏特）的光电导体在室温下在1.55微米处表现出约1.7微米的截止波长，响应度为1.5安/瓦，探测率为6.5×10厘米赫兹/瓦。重要的是，热蒸发工艺的特性使得能够制造出具有良好像素均匀性的基于硒化碲的42×42焦平面阵列，证明了这种独特材料系统用于红外成像传感器系统的潜力。
