Stress Controls The Electronic Structure And Transport Properties Of GeP₃

The GeP₃ has strong quantum confinement effect between layers,the monolayer and the bilayer are semiconductors,but triple layers or more have metal properties,bilayer also has high carrier mobilities,and it has good application prospect in lithium ion batteries.In this paper,Based on density functional theory software VASP and Nanodcal,we systematically studied the influence of stress on the electronic structure of monolayer GeP₃,and the effect of stress on electric current and voltage characteristics and photocurrent of device based on GeP₃.Our results show that for a monolayer of GeP₃,uniaxial compressive stress can be applied to change it from semiconductor to conductor.When the tensile stress is gradually increased,the band gap firstly increases and then decreases,the gap will reach 0.61eV when the stretching is about 4%.With the calculation results of elastic modulus,we find that mololayer of GeP₃ is easier to stretch,but difficult to compress.In addition,the strain mainly affect the effective mass of electrons and holes,and therefore has a great modulation effect on carrier mobility of monolayer GeP₃.We designed a molecular device with triple layers GeP₃ and mololayer GeP₃.Our results show that the device is in conduction state when the tensile strain is less than 4%,the deformation will change the current-voltage characteristics significantly,this feature can be used to design a GeP₃-based strain sensor device,and the electric current has a negative differential resistance characteristic near a voltage of 0.3 volts.When the tensile deformation exceeds 6%,the device exhibits semiconductor characteristics,and requires a bias voltage of about 0.3V to make the device in conducting state.We also studied the effects of stress on photocurrents of monolayer GeP₃ device.The relationship between the photocurrent and the polarization direction of light is found through fitting.Photocurrent is found to be particularly sensitive to the stress,the stress not only can change the value of the photocurrent,in some photon energy,the photocurrent can be increased by tens of times;the stress can also adjust the contribution of photon energy to the photocurrent.