Study On Photoelectric And Transport Properties Of Tellurene Nanodevices

Monoelement two-dimensional materials(Xenes)are important part of the two-dimensional material family.Xenes has many excellent mechanical,electrical,optical and thermal properties,so it is widely used in a variety of nanodevices.Recently,a new Xene—tellurene has been predicted in theory and synthesized in experiments.Tellurene has several different phases and exhibits excellent optical and electrical properties,but the research on the application of tellurene is still in its infancy.The properties of optoelectronic and transport devices based on different phases of tellurene were studied by using nonequilibrium Green's function combined with density functional theory.We constructed optoelectronic devices using two semiconductor phases of tellurene,?-Te and ?-Te,respectively,and calculated the photocurrent properties of the devices under linear polarized light irradiation.The results show that there is a trigonometric function relationship between the photocurrent and the polarization angle,and the photocurrent is saturated with the increase of the bias voltage of the device.The variation curve of photocurrent with photon energy forms photocurrent peaks at 1.4 and 1.8 eV,respectively.By analyzing the electronic structure of the material,we verify that the photocurrent peak corresponds to the specific energy level transition process of the electron.The phase of the photocurrent versus polarization angle curve of devices based on ?-Te will be reversed when the photon energy changes slightly,which leads to a significant increase in photocurrent and indicates that ?-Te can be used in optoelectronic switching devices.However,the curve of the devices based on ?-Te always maintains the same phase and has a large extinction ratio,so ?-Te can be used in polarized light detection devices.Then we build quantum transport devices using semiconductor phase ?-Te and metal phase ?-Te of tellurene and studied their properties and strain modulation.The device shows obvious negative differential resistance effect,which is caused by the energy level mismatch due to the electrode band gap of the device.Under the tensile strain,the width of the electrode band gap increases and the negative differential resistance effect increases,while under the compression strain,the electrode band gap disappears and the negative differential resistance effect weakens or disappears.The strain-tunable negative differential resistance effect shows that the device can be used in switching devices,logic circuits and other applications.The current peak value and the x-axis of the device under small bias voltage have a perfect exponential relationship,indicating that the device can be used as a distance sensor.Our study once again proved the excellent optical and electrical properties of tellurene,and proposed a number of practical applications of tellurene,which provided important theoretical support for the application of tellurene.