GROWTH-STUDIES ON IN0.5GA0.5AS/ALGAAS QUANTUM-WELLS GROWN ON GAAS WITH A LINEARLY GRADED INGAAS BUFFER

High indium content InGaAs/AlGaAs quantum wells (QWs) are useful for modulator and intersubband applications. Growth of these highly strained QWs on GaAs has been facilitated by the use of a linearly graded InGaAs buffer. We present here growth studies performed on these QW structures. Buffer parameters including buffer substrate temperature, buffer grading rate, and final buffer indium composition are studied. QW parameters including QW substrate temperature, the use of GaAs interface smoothing layers, and barrier substrate temperature are also investigated. Using near optimized growth conditions, narrow linewidth intersubband transitions are demonstrated.