Experimental determination of effective mass within the energy gap
Abstract With an effective mass approximation, it is possible to discuss the question: “What is the mass pertinent to the energy below the conduction band bottom?” Comparing photoluminescence data from AlGaAs/GaAs/AlGaAs quantum wells with precisely calculated bound energy levels, an appropriate effective mass within the barrier band gap is determined. It is concluded that the mass gradually decreases, with the energy below the conduction band bottom.
This paper presents a study of the technical efficiency of industries in a transitional economy: China. Using data for 28 manufacturing industries across 29 provinces and the Data Envelopment Analysis approach, the technical efficiency of each industry is measured and compared across regions and provinces. The determinants of differential technical efficiency performance are analysed, with a particular focus on the impact of trade orientation and foreign investment. Trade openness is found generally to have a positive effect on technical efficiency.