Research Of The Structural Characteristics Of Quantum Cascade Lasers Fundamental Materials

This dissertation mainly focuses on the analysis ofⅢ-Ⅴquantum cascade lasers(QCL)materials with the method of X-Ray Diffraction and Photoluminescence. The purpose is to get the accurate thickness and composition of the materials.Then the obtained result is compared with the expected structure to direct the growth of the materials,which is helpful for us to get the devices with better performance.The main results achieved in this work could be summarized as follows:1.The reciprocal Mapping of InP- based single- layer InGaAs and InAlAs materials is measured through the high- resolution X- Ray Diffraction Meter.Then the Misorientation- angle and the perpendicular mismatch are obtained.Moreover,the bulk mismatch and the composition of the materials are obtained through the Rocking Curves.2.The reciprocal Mapping of the InP- based InGaAs/InAlAs superlattice material is measured.Then the average perpendicular mismatch and the thickness of the period of the material are obtained.Then the thickness of every layer in the superlattice is obtained using the above information of the single- layer materials. At last,we can see the simulated curve matches very well with the measured curve,proving that the method used in this dissertation is reasonable.3.A series of photoluminescence curves of the InP- based single- layer InGaAs material are measured through Nicolet 860 FTIR Meter.The power of the experiment is the same while the temperature is different.The wave number and the energy of the peaks are obtained.Then the composition of the material is obtained according to the relationship of the temperature,composition and the energy of the forbidden- band.Then the result is compared with the information obtained through XRD to test whether the material could satisfy our expectation.