【作者】 王洪磊；

【导师】 李美成；

【作者基本信息】 哈尔滨工业大学 ， 材料物理与化学， 2007， 硕士

【摘要】 本文采用动力学蒙特卡罗方法（KMC）在SOS（Solid-on-Solid）模型基础上模拟了InAs／Ga_1-xIn_xSb超晶格的分子束外延（MBE）生长，利用包络函数方法计算了InAs／Ga_1-xIn_xSb的能带结构，在模拟和计算的基础上设计了特定截止波长的InAs／Ga_1-xIn_xSb超晶格结构。模拟研究发现，生长温度为663K时，在GaSb缓冲层上生长InAs层与GaInSb层时粗糙度曲线出现周期性振荡，与典型的RHEED图像相符，表明在该生长温度下生长的InAs／Ga_1-xIn_xSb能得到较好的薄膜质量。同时发现InSb型界面比GaAs型界面更加适合InAs／Ga_1-xIn_xSb超晶格的生长。另外，在生长Ga_1-xIn_xSb材料时，In含量越高，薄膜表面越粗糙。对InAs／Ga_1-xIn_xSb超晶格的能带结构计算表明，InAs／Ga_1-xIn_xSb的能带结构受到周期厚度和In含量的影响。InAs层和GaInSb层厚度都会影响超晶格的子带结构，InAs层变厚，HH1增加而C1下降，使得E_g减小；GaInSb层厚度变厚，C1和HH1均增加，E_g变化很小。In含量的变化由于同时改变了应变和GaInSb的能带参数，对InAs／Ga_1-xIn_xSb能带结构产生了巨大的影响，随着In含量的增加，C1下降，HH1增加，使得E_g迅速减小。在外延生长模拟和超晶格能带计算的基础上，选用InAs／Ga_0．9In_0．1Sb（3nm／2．7nm）结构设计p-i-n型光伏器件，其主要结构为：p+层为40个周期的InAs／GaInSb超晶格(GalnSb:Be 1×10¹⁷cm^-3)；i层为20个周期的非故意掺杂InAs／GaInSb超晶格；n+层为40个周期的InAs／GaInSb超晶格(InAs:Si 5×10¹⁷cm^-3)。计算该光伏器件在77K时的暗电流发现，其扩散电流较小，暗电流主要由复合电流和带间隧穿电流组成。当反向偏压小于16．5mV时，暗电流主要是复合电流；反向偏压超过16．5mV以后带间隧穿电流超过复合电流成为暗电流的主要组成部分。为InAs／GaInSb超晶格的器件设计奠定了基础。更多还原

【Abstract】 The Kinetic Monte Carlo （KMC） method based on Solid-on-Solid （SOS） model has been used to simulate the growth of InAs/Ga_1-xIn_xSb superlattice （SL） grown by Molecular Beam Epitaxy （MBE）. The band structure of InAs/Ga_1-x. In_xSb superlattice has been calculated by the Envelope Function method. On the basis of simulation and calculation, a SL photovoltaic deVice was designed.The simulation shows that, when the substrate temperature is 663K, the Roughness-Time curve of InAs/Ga_1-xIn_xSb growth on GaSb buffer displays a periodical oscillation, which agrees with the reported RHEED’s patterns. It indicates the high quality SLs growth by MBE at this temperature. The InSb-like interface in the InAs/Ga_1-xIn_xSb SL is smoother than the GaAs-like version. Furthermore, the quality of film degrades as the In content increasing in the Ga_1-x In_xSb growth.In general, the SL period and In content contribute the band structure change of InAs/Ga_1-xIn_xSb SL. The caulation result exhibits that, the energy of SL HH1 subband rises and C1 declines when InAs layer thickness increases, so band gap E_g decreases; on the other hand, increasing the thickness of GalnSb layer results in both C1 and HH1 rise then E_g has little changes. Because the In content affects on both strain and most band structure parameters of GalnSb, the SL band structure will vary significantly due to the changing content. Besides, the energy of C1 subband declines and HH1 rises with In content increasing, which results in the quick decrease of band gap.A p-i-n photodiode based on InAs/Ga_0.9In_0.1Sb （3nm/2.7nm） superlattice has been designed. The active layer consists of 20 periods unintentional doped SLs sandwiched between 40 periods p-type SLs (GalnSb: Be 1×10¹⁷cm^-3) and 40 periods n-type SLs (InAs: Si 5×10¹⁷cm^-3). The dark current at 77K mainly make up of the generation-recombination （G-R） current and band-to-band tunneling current. The G-R current dominates the dark current when the re Verse bias lower than 16.5mV, while beyond 16.5mV the band-to-band tunneling current exceeds.更多还原