School of Materials Science and Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332-0245, United States.
Key Laboratory of Advanced Ceramics and Machining Technology, Ministry of Education, School of Materials Science and Engineering, Tianjin University , Tianjin 300072, China.
ACS Nano. 2017 Jul 25;11(7):7118-7125. doi: 10.1021/acsnano.7b02811. Epub 2017 Jul 13.
Although silicon (Si) devices are the backbone of modern (opto-)electronics, infrared Si-photosensing suffers from low-efficiency due to its limitation in light-absorption. Here, we demonstrate a large improvement in the performance, equivalent to a 366-fold enhancement in photoresponsivity, of a Si-based near-infrared (NIR) photodetector (PD) by introducing the piezo-phototronic effect via a deposited CdS layer. By externally applying a -0.15‰ compressive strain to the heterojunction, carrier-dynamics modulation at the local junction can be induced by the piezoelectric polarization, and the photoresponsivity and detectivity of the PD exhibit an enhancement of two orders of magnitude, with the peak values up to 19.4 A/W and 1.8 × 10 cm Hz/W, respectively. The obtained maximum responsivity is considerably larger than those of commercial Si and InGaAs PDs in the NIR waveband. Meanwhile, the rise time and fall time are reduced by 84.6% and 76.1% under the external compressive strain. This work provides a cost-effective approach to achieve high-performance NIR photosensing by the piezo-phototronic effect for high-integration Si-based optoelectronic systems.
尽管硅 (Si) 器件是现代 (光) 电子学的支柱，但由于其在光吸收方面的限制，红外 Si 光传感的效率仍然很低。在这里，我们通过在异质结上沉积一层 CdS 层引入压电光电效应，证明了 Si 基近红外 (NIR) 光电探测器 (PD) 的性能得到了显著提高，其光响应率提高了 366 倍。通过对外施加-0.15‰的压缩应变，可以在局部结处诱导载流子动力学调制，从而使 PD 的光响应率和探测率提高了两个数量级，峰值分别高达 19.4 A/W 和 1.8×10 cm Hz/W。所获得的最大响应率明显大于商用 Si 和 InGaAs PD 在 NIR 波段的响应率。同时，在外加压缩应变下，上升时间和下降时间分别减少了 84.6%和 76.1%。这项工作为基于 Si 的高集成光电系统通过压电光电效应实现高性能 NIR 光传感提供了一种具有成本效益的方法。
