Yuan Xiu-hua

Effects of an InGaAs Cap Layer on the Optical Properties of InAs Quantum Dot Molecules

Self-assembled InAs quantum dot molecules are grown on GaAs substrates without following any special protocols by using metal-organic chemical vapor deposition. The effects of indium composition and the thickness of the InGaAs cap layer on the optical properties of InAs quantum dot molecules are investigated by photoluminescence. With increasing indium composition and thickness of the InGaAs cap layer, the ground-state wavelength of the emission spectrum redshifts and the peak intensity decreases. In addition, the structural and optical properties of quantum dots and quantum dot molecules are comparatively studied, and the results show that when quantum dots turn into quantum dot molecules, the emission wavelength red shifts.

A novel pressure sensor calibration system based on a neural network

According to the specific input-output characteristics of a pressure sensor, a novel calibration algorithm is presented and a calibration system is developed to correct the nonlinear error caused by temperature. In contrast to the routine BP and RBF, curve fitting based on RBF is first used to get the slope and intercept, and then the voltage-pressure curve is described. Test results show that the algorithm features fast convergence speed, strong robustness and minimum SSE (sum of squares for error). It is proven by practical applications that this calibration system works well and the measurement precision is better than the design demands. Furthermore, this calibration system has a good real-time capability.