Accumulation layer and interface effects in doped nonabrupt GaAs/AlxGa1-xAs heterojunctions

A theoretical model is proposed to describe doped nonabrupt GaAs/Al_xGa_1-xAs heterojunctions. It is used to study interface effects on the transmission properties and energy levels of electrons in these heterostructures. It is showed that interface effects are important in the case of high doping levels, and wide GaAs/Al_xGa_1-xAs interfaces.     

GaAs/AlxGa1-xAs球形量子点中的电子结构

详细讨论了GaAs/AlxGa1-xAs球形量子点内的单电子束缚能级随量子点半径、Al组分以及外电场的变化规律,并计算了考虑量子点内外电子有效质量不同后对电子能级的修正. 另外,用解析和平面波展开两种方法对球形量子点内的电子能级进行了计算,并对计算结果做了比较,发现它们符合的很好. 结论和方法为量子点的研究和应用提供了有益的信息和指导.     

Near-surface and bulk deep trap states in AlxGa1-xAs/GaAs

We have measured the field-effect deep-level transient spectra of Al_xGa_1-xAs/GaAs (where x=0.385) at different reverse-bias fields to probe the near-surface deep trap and bulk deep trap states. In the temperature range 77 to 380 K and for a reverse-bias field -1 to -5 V/cm, four major deep traps were identified. The results of our investigation indicate a distinct effect on the deep-level spectra. Three of the deep trap states E1, E2 and E3 showed definite peak enhancement with the applied reverse-bias field and were identified as bulk deep trap states. The fourth deep trap state E4 was a very weak deep trap state and it showed a decrease of the peak height with the applied reverse-bias field. It was labeled as a near-surface deep trap state. PACS 73.60.Fw     

Strain-confined wires and dots at a GaAs/AlxGa1-xAs interface

We have observed lateral exciton confinement at the GaAs/Al_xGa_1-xAs interface. The confinement is achieved in both the growth and lateral directions by the strain potential under an amorphous carbon stressor. The potential welt varies from 15 meV to 40 meV for different stressor sizes. We have also made transient measurements on this structure, which show efficient exciton transfer from the bulk GaAs to the confined region.