First-Principles Study Of The Temperature Effect Of Electronic Properties Of Transparent Semiconductor Copper Iodide

Transparent conductive materials have important applications in planar display,electronic information,photovoltaic and other fields.n-type transparent semiconductors and their doping technologies are relatively mature,while the development of p-type transparent semiconductors is limited by rare materials,lower mobility and higher cost.In recent years,?-phase Cu I emerges a promising p-type transparent semiconductor.This semiconductor has advantages of high carrier mobility and low cost,so that it has strong application potential.At present,the electronic and thermoelectric properties of ?-phase Cu I have been studied,but all of them are based on the electronic structure at zero temperature,without considering temperature effect on the electronic structure,which may mislead the theoretical study of its properties at room temperature.Therefore,we investigate the electrical and thermoelectric properties of Cu I at room temperature by studying its temperature effect of electronic structure.Firstly,using density-functional-theory-based approaches,we investigate the temperature effect on electronic structure of ?-phase Cu I at room temperature.Temperature alters the electronic structure in two ways,the electron-phonon coupling interaction and lattice expansion.We find that the band gap of Cu I increases monotonically with temperature increasing,and the electron-phonon coupling interaction plays a major role.Secondly,we investigate carrier transport properties of Cu I based on the electronic structure at finite temperature,including the hole effective mass and mobility of Cu I.The theoretical results are consistent with the existing experimental results.Finally,based on semi-classical Boltzmann transport theory and electronic structure at finite temperature,we study the thermoelectric performance of Cu I at different temperatures.We find that the higher the carrier concentration,the stronger the effect of electron-phonon coupling interaction on the thermoelectric performance of Cu I;the higher temperature,the stronger the effect of the electronphonon coupling interaction on thermoelectric performance of Cu I.In conclusion,we introduce temperature effect into the calculation of the electronic structure and transport properties of Cu I.We not only demonstrate the importance of temperature effect on the electrical and thermoelectric properties of Cu I,but also develop a set of calculation methods to study the carrier mobility,thermoelectric coefficient at finite temperature.We believe that these methods will be powerful tools to study the relevant properties more accurately in the future.