Shuchi Kaushik1,Sahin Sorifi1,Rajendra Singh1
Indian Institute of Technology Delhi1
Shuchi Kaushik1,Sahin Sorifi1,Rajendra Singh1
Indian Institute of Technology Delhi1
Two-dimensional layered materials (2DLMs) have revolutionized the field of optoelectronics due to their appealing properties of strong-light matter interaction, atomic-level thickness, and ability to form van der Waals heterostructures.<sup>[1]</sup> However, most of the 2DLMs possess a narrow bandgap and are, therefore, suitable for visible or infra-red photodetection. In addition, the poor stability of some of the 2DLMs is a matter of concern as far as practical applications are concerned.<sup>[2]</sup> Owing to its wide bandgap of 5.955 eV<sup>[3]</sup> and high-temperature stability,<sup>[4]</sup> hexagonal-boron nitride (h-BN) has emerged as an ideal 2DLM for fabricating deep UV photodetectors (PDs) that may find a place in commercial applications requiring high-temperature robustness.<sup>[5]</sup><br/>In this work, we explore the high-temperature stability of metal-semiconductor-metal (MSM) deep UV PDs fabricated on high-quality mechanically exfoliated h-BN flakes. The MSM structure of the device is fabricated on individual flakes using electron beam lithography. High work function metal platinum (Pt) is deposited using sputtering to obtain Pt/h-BN/Pt MSM PDs. The device exhibits an ultra-low dark current of 1.96 × 10<sup>-14</sup> A at 10 V. Upon shining the deep UV wavelength of 205 nm, the current enhances by ten times, reaching the value of 1.79 × 10<sup>-13</sup> A. The performance parameters of photo-to-dark current ratio (PDCR) and responsivity are calculated to be 8.2 and 5.2 mA/W, respectively, at 10 V. A stable multicycle response of the PD is observed on testing the device up to a high temperature of 473 K. The responsivity is found to increase with temperature, giving a maximum value of 30 mA/W at 473 K, thereby establishing the high-temperature performance of the deep UV PD.<br/><b>References </b><br/>[1] S. Kaushik, R. Singh, <i>Adv. Opt. Mater.</i> <b>2021</b>, <i>2002214</i>, 1.<br/>[2] S. Kaushik, S. Sorifi, R. Singh, <i>Photonics Nanostructures Fundam. Appl.</i> <b>2021</b>, <i>43</i>, 100887.<br/>[3] G. Cassabois, P. Valvin, B. Gil, <i>Nat. Photonics</i> <b>2016</b>, <i>10</i>, 262.<br/>[4] L. H. Li, Y. Chen, <i>Adv. Funct. Mater.</i> <b>2016</b>, <i>26</i>, 2594.<br/>[5] W. Zheng, R. Lin, Z. Zhang, F. Huang, <i>ACS Appl. Mater. Interfaces</i> <b>2018</b>, <i>10</i>, 27116.