【摘要】 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。更多还原

【Abstract】 InAs(1.2 nm)/GaSb(2.4 nm)superlattices with integral crystallization and smooth surface morphology were grown on GaSb(100)substrates by molecular beam epitaxy(MBE).With the temperature arising from 70 K to room temperature,the Raman shift of longitudinal optical(LO)moved 5 cm-1 to lower energy.The shift-temperature coefficient was 0.023 cm-1 /K.The photoluminescence(PL)peak composed of band-to-band and binding exciton radiation recombination was located at the range of 2.4-2.8 μm.The 2.55 μm PL peak showed a little red shift with the temperature increasing from 15 K to 150 K.The shift owing to the change of the width between the electron band in InAs and the hole band in GaSb is smaller than that of the band gap in the bulk materials.The PL intensity became stronger when arising the temperature from 15 K to 50 K,and weaker from 60 K to 150 K.It behaved different independence-temperature at separate temperature range.更多还原