Principle And Design Of The Optoelectronic Devices Based On The Ⅳ-Ⅵ Compound Germanium Selenide Heterojunction

Group Ⅳ-Ⅵ compound materials possess a surface undulating fold structure similar to that of phosphorene and exhibit significant in-plane anisotropy,which has attracted great interest due to their unique structural properties and potential optoelectronic applications.In this paper,we investigate the current-voltage properties of GeSe nanostructures and their optoelectronic effects by means of substitution doping and heterojunction construction based on the density general function theory combined with the non-equilibrium Green’s function first-principle research method using the in-plane anisotropic optical and electrical properties of group Ⅳ-Ⅵ compounds germanium selenide,and provide theoretical references for the design of GeSe/SnSe heterojunction-based optoelectronic devices.The main research contents are as follows:1)To study the device current-voltage characteristics of intrinsic GeSe two-terminal devices under doping conditions.Through the regulation of device current-voltage characteristics by different central semiconductor channel lengths,it is found that the device current increases with the increase of positive bias voltage and decreases with the increase of negative bias voltage,showing a significant negative differential resistance effect;as the channel length of the central semiconductor part increases,when the intrinsic germanium selenide nanoribbon length is twice the length of the doped part of germanium selenide nanoribbon,the current is almost always zero with the increase of bias voltage,and the device shows a significant rectification characteristic.2)Studies on the photoelectric effect of GeSe under doping conditions have shown that non-doped as well as phosphorus P,As and Sb atoms alternatively doped monolayer GeSe produce photocurrent under polarized light irradiation,and the magnitude of photocurrent varies as a sinusoidal complex function with the change of polarized light angle.It is found that the magnitudes of photocurrents produced by different atomic doping photodetectors in the central region of light irradiation are different,but in general,the doping effectively increases the magnitude of photocurrents produced by GeSe.Further analysis on the polarization sensitivity of GeSe photodetectors with different doping systems found that the polarization sensitivity of GeSe photodetectors with P doping and Sb doping decreased,while the polarization sensitivity of GeSe photodetectors with As doping was significantly enhanced in comparison.Thus,As-doped GeSe photodetectors have the best optoelectronic performance,and As-doped GeSe photodetectors have the highest photocurrent and sensitivity under the same position doping and light conditions.3)To study the optoelectronic effect of GeSe/SnSe transverse planar heterojunction under zero bias voltage.The results show that the photocurrent generated by the intrinsic GeSe optoelectronic device under zero bias in the sawtooth transport direction varies with the polarization light angle according to the sinusoidal law,and the photocurrent generated by the intrinsic GeSe optoelectronic device under zero bias in the armchair transport direction varies with the polarization light angle according to the cosine law,and the above results do not change with the type of polarization light and are consistent with the theory of photoelectric effects.The overall photocurrent of GeSe/SnSe heterojunction devices at zero bias is larger than that of intrinsic GeSe devices,and the study on optoelectronic devices at zero bias can greatly reduce the interference of dark current on the study results.The results show that GeSe/SnSe planar heterojunction is a good candidate material for optoelectronic devices,which produce larger photocurrent and better polarization sensitivity.