Band structure model of biaxial strained Ge paralleled to the (001) plane was constructed based on the deformation potential theory .Results indicate that germanium ,under biaxial strain paralleled to the (001) plane ,can be tuned to a direct band gap material or an indirect band gap material with the lowest energy Δ4point .Band gap of the strained Ge can be expressed by four linear functions : Ge under highly compressive strain more than 2.06% is an indirect band semiconductor with Гas the minimum conduction band ,and band gap will decrease linearly with the compressive strain . For the tensile strain higher than 1.77%,Ge is tuned to a direct band material with Гas the minimum conduction band ,and band gap will decrease linearly with the tensile strain .When the strain in Ge is between －2.06% and 1.77%,Ge acts as an indirect band semiconductor with Las the minimum conduction band , band gap will increase linearly with compressive strain and decrease linearly with compressive strain slightly . Results can be beneficial to the guidance for the application of Ge materials in optoelectronics .%本文基于形变势理论构建(001)面双轴应变Ge材料的能带结构模型.计算结果表明(001)面双轴应变可以将Ge的能带从以 L能谷为导带底的间接带半导体调控到以 Δ4能谷为导带底的间接带半导体或者以 Г能谷为导带底的直接带半导体.同时室温下Ge的带隙与应变的关系可用四段函数来表示:当压应变将Ge材料调控为以 Г能谷为导带底的间接带半导体后,每增加1% 的压应变,禁带宽度将线性减小约78.63meV ;当张应变将Ge材料调控为直接带半导体后,张应变每增加1%,禁带宽度将线性减小约177.98meV ;应变介于－2.06% 和1.77% 时,Ge将被调控为以L能谷为导带底的间接带半导体,禁带宽度随着压应变每增加1% 而增加11.66meV ,随着张应变每增加1% 而线性减小约88.29meV .该量化结果可为研究和设计双轴应变Ge材料及其器件提供理论指导和实验依据.
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