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采用分子束外延(MBE)技术,在GaSb(100)衬底上外延生长晶体结构完整和表面平整的Ⅱ型超晶格InAs(1.2nm)/GaSb(2.4nm)。拉曼光谱表明:随着温度从70K升高至室温,由于热膨胀作用和光声子散射过程中的衰减,超晶格纵光学声子拉曼频移向低波数方向移动5cm-1,频移温度系数约为0.023cm-1/K。光致发光(PL)峰在2.4～2.8μm,由带间辐射复合和束缚激子复合构成,2.55μmPL峰随温度变化(15～150K)发生微小红移,超晶格中InAs电子带与GaSb空穴带带间距随温度变化比体材料的禁带宽度小。PL发光强度在15～50K随温度升高而升高,在60～150K则相反,并在不同温度段表现出不同的温度依赖关系。
The type Ⅱ superlattice InAs (1.2nm) / GaSb (2.4nm) with complete crystal structure and smooth surface was epitaxially grown on GaSb (100) substrate by molecular beam epitaxy (MBE). The Raman spectra show that as the temperature rises from 70 K to room temperature, the superlattice longitudinal optical phonon Raman shift shifts to 5 cm-1 in the lower wavenumber direction due to thermal expansion and photoacoustic scattering. The frequency shift temperature The coefficient is about 0.023 cm-1 / K. The photoluminescence (PL) peak at 2.4-2.8μm consisted of interband radiation recombination and bound exciton recombination. The 2.55μm PL peak shifted slightly with temperature (15-150K), and the InAs band in the superlattice interacted with GaSb The hole spacing varies with temperature and is smaller than the forbidden band width of the bulk material. The luminescence intensity of PL increases with increasing temperature from 15K to 50K and from 60K to 150K, and shows different temperature dependences at different temperatures.