Investigation of Energy Band Structures of InAs/GaSb and M Structure Superlattices
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摘要: 本文通过k·p方法研究了传统InAs/GaSb超晶格和M结构超晶格的能带结构。首先，计算了不同周期厚度的InAs/GaSb超晶格的能带结构，得到用于长波超晶格探测器吸收层的周期结构。然后，计算了用于超晶格长波探测器结构的M结构超晶格的能带结构，并给出长波InAs/GaSb超晶格与M结构超晶格之间的带阶。最后，基于能带结构，计算出长波超晶格与M结构超晶格的态密度，进而得出的载流子浓度（掺杂浓度）与费米能级的关系。这些材料参数可以为超晶格探测器结构设计提供基础。
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关键词:
- k·p方法 /
- InAs/GaSb超晶格 /
- M结构超晶格 /
- 能带结构 /
- 掺杂浓度
Abstract: In this study, the band structures of conventional InAs/GaSb and M structure super lattices are investigated using the k·p method. First, the band structures of InAs/GaSb super lattices with various period thickness are calculated, and the period structure used for a longwave super lattice detector is obtained. Subsequently, the band structure of the M structure super lattice, which is prevalently employed in longwave super lattice infrared detectors, is also calculated. The band offset between a longwave InAs/GaSb super lattice and M structure super lattice is provided. Furthermore, based on the band structures, the relationship between the carrier density (doping density) and the position of the Fermi level for longwave InAs/GaSb and M structure super lattices is obtained. This was followed by a density of states (DOS) calculation. These calculated material parameters can provide the foundation for designing super lattice infrared detectors.-
Key words:
- k·p method /
- InAs/GaSb superlattice /
- M structure super lattice /
- energy band structure /
- doping density
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图 1 InAs/GaSb超晶格带隙随InAs层厚度的关系
Figure 1. Variation of band gap of InAs/GaSb superlattice with respect to InAs layer thickness.
图 2 7 MLs GaSb/ 1 ML InSb/ 14 MLs InAs/ 1 ML InSb能带带阶排列
Figure 2. Band edge alignment of 7 MLs GaSb/ 1 ML InSb/ 14 MLs InAs/ 1 ML InSb
图 3 14 MLs InAs/ 7 MLs GaSb超晶格的能带色散关系，能量原点为GaSb体材料的价带顶
Figure 3. Energy band dispersion of 14 MLsInAs/ 7 MLs GaSb superlattice, the energy origin is set as the top of GaSb valence band
图 4 14 MLs InAs/ 7 MLs GaSb超晶格在单周期内的波函数
Figure 4. Wave function of 14 MLs InAs/ 7 MLs GaSb superlattice in unit cell
图 5 18 MLs InAs / 1 ML InSb/ 3 MLs GaSb / 5 MLs AlSb /3 MLs GaSb/ 1 ML InSb能带带阶排列
Figure 5. Band edge alignment of 18 MLs InAs / 1 ML InSb/ 3 MLs GaSb / 5 MLs AlSb / 3 MLs GaSb/ 1 ML InSb
图 6 18 MLs InAs / 3 MLs GaSb / 5 MLs AlSb / 3 MLs GaSb M结构超晶格的能带色散关系，能量原点为GaSb体材料的价带顶
Figure 6. Energy band dispersion of 18 MLs InAs / 3 MLs GaSb / 5 MLs AlSb / 3 MLs GaSb M structure superlattice, the energy origin is set as the top of GaSb valence band
图 7 14 MLs InAs / 7 MLs GaSb超晶格和18 MLs InAs / 3 MLs GaSb / 5 MLs AlSb / 3 MLs GaSbM结构超晶格的态密度
Figure 7. The density of states for 14 MLs InAs / 7 MLs GaSb superlattice and 18 MLs InAs / 3 MLs GaSb / 5 MLs AlSb / 3 MLs GaSb M structure superlattice
图 8 掺杂浓度与费米能级位置之间的关系
Figure 8. The relationship between doping density and Fermi energy level
表 1 14 MLs InAs/ 7 MLs GaSb超晶格和18 MLs InAs/ 3 MLs GaSb/ 5 MLs AlSb/ 3 MLs M结构超晶格的关键能带参数
Table 1. Critical energy band parameter of 14 MLs InAs/ 7 MLs GaSb superlattice and 18 MLs InAs/ 3 MLs GaSb/ 5 MLs AlSb/ 3 MLs M structure superlattice
Structure Effective energy
gap (Eg)/eVBottom of conduction
band (Ec)/eVTop of valence
band (Ev)/eVΔEc/meV ΔEv/meV 14 MLs InAs/ 7 MLs GaSb superlattice 0.1235 0.0701 -0.0534 -- -- 18 MLs InAs/ 3 MLs GaSb/ 5 MLs AlSb/ 3 MLs M structure superlattice 0.2133 0.0612 -0.1521 -8.9 -98.7 
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