Crystal Growth of Thallium Containing III-V Semimetal-Semiconductor Alloys and Search of New Physical Properties

用气态源分子束外延技术，用Tl，In，Ga元素，以及热裂解的砷和磷，在InP衬底上生长了四元半导体TlInGaAs，TlInGaP。生长过程中的衬底温度为450ﾟC。X射线衍射和电子探针测量证实了TlInGaAs和TlInGaP的成功生长。结果表明，TlInGaAs的Tl组分在生长过程中随着Tl流量的增加而增加。观察到TlInGaAs的光致发光峰值随Tl组分的增加而增加，禁带宽度随Tl的掺入而减小。光致发光光谱的温度变化曲线表明，Tl InGaAs的带隙能量随温度的变化比Tl的温度变化要慢对于Tl组分为6%的TlInGaAs，观察到了与温度几乎无关的带隙能.这一结果与我们预期的性质很好地吻合.我们还生长了InP/TlInGaAs/InP的双异质结结构.从X射线衍射和EPMA测量表明，在界面上没有发生III族原子的互扩散.此外，我们还生长了InP/TlInGaAs/InP的双异质结结构.从X射线衍射和EPMA测量表明，在界面上没有发生III族原子的互扩散.此外，对于Tl组分为6%的Tl InGaAs，我们观察到了几乎与温度无关的禁带能通过对TlInGaP的光电导谱随温度变化的测量，观察到了TlInGaP层的光致发光强度随温度的变化。首次观察到了尖端的拉曼信号。拉曼峰位于InP的低波长处。这表明TlInGaP在与温度无关的波长激光二极管中具有良好的应用前景。

Quaternary semiconductors TlInGaAs, TlInGaP were grown on InP substrates by gas source MBE using elemental Tl, In and Ga, and thermally cracked arsine and phosphine.Substrate temperature during growth was 450ﾟC.X-ray diffraction and EPMA measurements confirmed the successful growth of TlInGaAs and TlInGaP.It was found that Tl composition of TlInGaAs increases with Tl flux during growth.Photoluminescence (PL) emission was observed from the grown TlInGaAs.PL peak wavelength was observed to increase with Tl composition and it was found that the bandgap is decreased by incorporation of Tl.Temperature dependence of PL spectra showed that the temperature variation of bandgap energy is slower than those of GaAs, InP and InAs.For the TlInGaAs with Tl composition of 6%, nearly temperature-independent bandgap energy was observed.This result agrees well with our expected properties.We also have grown the double-hetero (DH) structure of InP/TlInGaAs/InP.From the X-ray diffraction and EPMA measurements on this DH structure showed that the interdiffusion of group III atoms at the interfaces was not occurred.Furthermore, we have observed the enhancement of PL intensities from TlInGaAs layer by the formation of DH structures.Slower temperature variation of bandgap energy was also observed for TlInGaP by the measurement of temperature dependence of photoconductance spectra.We have observed the TIP Raman signals for the first time.The Raman peaks were located at lower wavenumbers of those of InP.It was suggested that TlInGaAs is promising for the application to the temperature-independent wavelength laser diodes.