Das Mahapatra Ayon, Das Amaresh, Ghosh Shuvaraj, Basak Durga
School of Physical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
ACS Omega. 2019 Jan 16;4(1):1364-1374. doi: 10.1021/acsomega.8b03084. eCollection 2019 Jan 31.
TiO nanorods (NRs) have generated much interest for both fundamental understanding of defect formation and technological applications in energy harvesting, optoelectronics, and catalysis. Herein, we have grown TiO NR films on glass substrates using a self-seeded approach and annealed them in H ambient to modify their surface defects. It has been shown that broad-band photosensing properties of Au/self-seeded TiO NR/Au-based two back-to-back Schottky junctions (SJs) for a broad wavelength of light are much superior as compared to those of the pristine and the control samples. Photoresponsivity values for the H-annealed sample are 0.42, 0.71, 0.07, and 0.08 A/W for detecting, respectively, 350, 400, 470, and 570 nm lights. Very low dark current and high photocurrent lead to a gain value as high as 1.85 × 10 for 400 nm light. Unprecedentedly modified NR-based SJs show excellent photoresponsivity for detecting as low as 25, 36, 48, and 28 μW/cm power densities of 350, 400, 470, and 570 nm lights, respectively. It is found that Ti defects play a key role in an efficient photoelectron transfer from TiO to Au. Our work, for the first time, highlights the simplicity and reveals the rationale behind the excellent properties of Au/self-seeded TiO NR film/Au back-to-back SJs.
TiO纳米棒（NRs）在缺陷形成的基础理解以及能量收集、光电子学和催化等技术应用方面引起了广泛关注。在此，我们采用自种子法在玻璃基板上生长了TiO NR薄膜，并在氢气环境中对其进行退火处理以改变其表面缺陷。结果表明，与原始样品和对照样品相比，基于金/自种子TiO NR/金的两个背靠背肖特基结（SJs）在宽波长光下的宽带光传感特性要优越得多。对于H退火样品，在分别检测350、400、470和570 nm光时，光响应率值分别为0.42、0.71、0.07和0.08 A/W。极低的暗电流和高光电流导致在400 nm光下增益值高达1.85×10。前所未有的改性NR基SJs在分别检测350、400、470和570 nm光的低至25、36、48和28 μW/cm²功率密度时显示出优异的光响应率。研究发现，Ti缺陷在从TiO到Au的有效光电子转移中起关键作用。我们的工作首次突出了其简单性，并揭示了金/自种子TiO NR薄膜/金背靠背SJs优异性能背后的原理。
