First-principles Study Of Optical Properties Of Germanium Doped With Phosphorus And Bismuth

Semiconductor germanium did not attract people's attention for a long time after it was discovered,because few germanium-bearing minerals were found at that time,and the purification and preparation of germanium and its compounds were difficult at that time.In the 1940 s and 1950 s,radio technology developed rapidly,and soon radio technology could be applied to shorter wavelengths.However,the widely used vacuum tubes could not be used at this wavelength,which prompted people to study transistors.Since then,the metallurgical technology of germanium developed rapidly and the properties of germanium began to be widely studied.Due to its high electron mobility,high frequency and high strength,germanium is widely used in high frequency,far infrared,aerospace and other military fields.At present,there are many reports on germanium,and there are mainly the following methods.The optical gain of germanium can be changed by controlling the number of atomic layers of germanium.The relationship between the direct and indirect bands of germanium can be changed by adjusting the upward strain pressure.The dielectric function and absorption coefficient of germanium were changed by doping a small amount of silicon into germanium.On the paper,the semiconductor germanium was doped by n-type doping at various concentrations,and the doping concentrations were 1.563%,2.083% and 3.125%,and the doped elements were phosphorus and bismuth.In this article,the electronic state density and optical properties of the doped system are calculated and studied based on the first principle under the framework of density functional theory,and the electronic state density and optical properties before and after doping are calculated and analyzed.It can be seen from the conclusion that the Fermi level of the system will drift to the direction of high energy after the doping of phosphorus and bismuth.The dielectric function,refractive index and absorption coefficient are greatly affected in the low energy range of the incident photon,but the extinction coefficient and absorption coefficient are affected in the high energy range of the incident photon.Doping will affect the reflectivity in all energy ranges,among which the reflectivity only increases in the middle energy range and decreases in the other two energy ranges.The higher the doping concentration is,the smaller the peak of the energy loss function will be formed at the higher energy.Some opinions on the optical application of germanium can be drawn from these conclusions,and the influence of doping concentration and energy size on the optical application can be studied more specifically according to the conclusions.