High-Crystallinity Epitaxial SbSe Thin Films on Mica for Flexible Near-Infrared Photodetectors.

The V-VI binary chalcogenide, SbSe, has attracted considerable attention for its applications in thin film optoelectronic devices because of its unique 1D structure and remarkable optoelectronic properties. Herein, we report an SbSe thin film epitaxially grown on a flexible mica substrate through a relatively weak (van der Waals) interaction by vapor transport deposition. The epitaxial SbSe thin films exhibit a single (120) out-of-plane orientation and a 0.25° full width at half-maximum of (120) rocking curve in X-ray diffraction, confirming the high crystallinity of the epitaxial films. The SbSe(120) plane is epitaxially aligned on mica(001) surface with the in-plane relationship of SbSe[2̅10]//mica[010] and SbSe[001]//mica[100]. Compared to the photodetector made of a nonepitaxial SbSe film, the photocurrent of the epitaxial SbSe film photodetector is almost doubled. Furthermore, because of the flexibility and high sensitivity of the epitaxial SbSe film photodetector on mica, it has been successfully employed to detect the heart rate of a person. These encouraging results will facilitate the development of epitaxial SbSe film-based devices and potential applications in wearable electronics.