Tuning the Optical Absorption Property of GeSe Thin Films by Annealing Treatment

Abstract

As an emerging promising photovoltaic absorber material, GeSe has attracted significant interest recently due to its simple binary composition, attractive optical and electrical properties as well as earth‐abundant and low‐toxic constituents. However, no systematic study on the absorption property tuning of GeSe has been reported. Here, first it is shown that the crystallization temperature of amorphous GeSe is about 330 °C through differential thermal analysis and temperature‐dependent X‐ray diffraction. Next, GeSe films with tunable absorption property in the range of 1.79–1.14 eV are fabricated by annealing amorphous GeSe films at different temperatures. Finally, through the combined analysis of bandgaps measured by transmission spectroscopy and nanosheet thickness characterized by cross‐sectional high‐resolution transmission electron microscopy, the blue shift of bandgap with decreasing thickness of nanosheets has been attributed to the quantum confinement effect. Such continuously tunable absorption property of GeSe films makes it more useful for further optoelectronics.

GeSe photovoltaics: doping, interfacial layer and devices

“…Previous literature studying the structure of thin film GeSe has shown a strong orientation preference for the (100) plane experimentally and a theoretical study shows that the total energy of the plane is lower than those of alternative common planes. 19–22,33,34 The incorporation of the Sb 2 Se 3 interfacial layer has been shown previously to make the (111) plane more prominent, consistent with the findings in this study. 23…”

GeSe thin-film solar cells

“…4d and e). 81 There have been several reports about the fabrication of polycrystalline GeSe thin films through this method. However, these samples had always a residue of amorphous phase GeSe, and suffered from adverse film orientation, which may significantly influence the performance of GeSe solar cells.…”

Refractive Uses of Layered and Two-Dimensional Materials for Integrated Photonics

“…PVD is less-widely used for LM film synthesis than ssCVD, CVD, and MOCVD. A number of main-group metal monochalcogenides that evaporate congruently and that have fairly high vapor pressure have been synthesized as thin films by PVD, including SnS, SnSe, GeS, and GeSe. − bP and TMD thin films have been synthesized by PLD and sputtering. − …”