Effect of interface on mid-infrared photothermal response of MoS2 thin film grown by pulsed laser deposition
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2017-07-04 |
| Journal | Nano Research |
| Authors | Ankur Goswami, Priyesh Dhandaria, Soupitak Pal, Ryan McGee, Faheem Khan |
| Institutions | University of California, Santa Barbara, University of Alberta |
| Citations | 37 |
Abstract
Section titled āAbstractāThis study reports on the mid-infrared (mid-IR) photothermal response of multilayer MoS2 thin films grown on crystalline (p-type silicon and c-axis-oriented single crystal sapphire) and amorphous (Si/SiO2 and Si/SiN) substrates by pulsed laser deposition (PLD). The photothermal response of the MoS2 films is measured as the changes in the resistance of the MoS2 films when irradiated with a mid-IR (7 to 8.2 Ī¼m) source. We show that enhancing the temperature coefficient of resistance (TCR) of the MoS2 thin films is possible by controlling the film-substrate interface through a proper choice of substrate and growth conditions. The thin films grown by PLD are characterized using X-ray diffraction, Raman, atomic force microscopy, X-ray photoelectron microscopy, and transmission electron microscopy. The high-resolution transmission electron microscopy (HRTEM) images show that the MoS2 films grow on sapphire substrates in a layer-by-layer manner with misfit dislocations. The layer growth morphology is disrupted when the films are grown on substrates with a diamond cubic structure (e.g., silicon) because of twin growth formation. The growth morphology on amorphous substrates, such as Si/SiO2 or Si/SiN, is very different. The PLD-grown MoS2 films on silicon show higher TCR (ā2.9% Kā1 at 296 K), higher mid-IR sensitivity (ĪR/R = 5.2%), and higher responsivity (8.7 VĀ·W-1) compared to both the PLD-grown films on other substrates and the mechanically exfoliated MoS2 flakes transferred to different substrates.