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以(001)和(111)价带Lutinger-Kohn哈密顿量为基础,讨论了这两种取向的量子阱的能带结构、态密度(DOS)、跃迁矩阵元和增益特性.由于材料结构的各向异性,(111)取向的量子阱在平行生长面内有较小的重空穴有效质量,无应变和压应变激光器可以很好地利用这一点.而(001)取向的量子阱虽有较小的平面内轻空穴有效质量,但并不比(111)量子阱的小多少;加上(001)量子阱的价带耦合效应强,使其DOS比(111)量子阱的大,在相同载流子注入下,张应变(111)量子阱的增益系数比相应(001)量子阱的要高.所以张应变(111)量子阱激光器仍然比相应的(001)量子阱激光器性能要好.可以认为匹配和压应变的(111)激光器优异的性能不仅来自小的面内有效质量,也来自于弱的价带耦合效应
Based on the Lutinger-Kohn Hamiltonian of the (001) and (111) valence band, we discuss the energy band structure, DOS, transition matrix elements and gain characteristics of these two oriented quantum wells. Due to the anisotropy of the material structure, the (111) -oriented quantum well has a small effective weight of heavy holes in the parallel growth plane, which is best exploited by non-strain and compressive-strain lasers. The (001) -oriented quantum well has a smaller effective mass of light holes in plane but is not much smaller than the (111) quantum well. Coupled with the (001) quantum well, the valence band coupling effect makes it DOS The gain coefficient of the tensile strain (111) quantum well is higher than that of the corresponding (001) quantum well under the same carrier injection as that of the (111) quantum well. The tensile strain (111) quantum well laser still performs better than the corresponding (001) quantum well laser. The excellent performance of matched and compressively strained (111) lasers can be considered not only from small in-plane effective masses but also from weak valence band coupling effects