Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Electrical characterisation of deep level defects in Be-doped AlGaAs grown on (100) and (311)A GaAs substrates by MBE | Mari et al. Nanoscale Research Letters 2011 6 180 http content 6 1 180 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Electrical characterisation of deep level defects in Be-doped AlGaAs grown on 100 and 311 A GaAs substrates by MBE 1 11 11 2 Riaz H Mari Muhammad Shafi Mohsin Aziz Almontaser Khatab David Taylor Mohamed Henini Abstract The growth of high mobility two-dimensional hole gases 2DHGs using GaAs-GaAlAs heterostructures has been the subject of many investigations. However despite many efforts hole mobilities in Be-doped structures grown on 100 GaAs substrate remained considerably lower than those obtained by growing on 311 A oriented surface using silicon as p-type dopant. In this study we will report on the properties of hole traps in a set of p-type Be-doped samples grown by molecular beam epitaxy on 100 and 311 A GaAs substrates using deep level transient spectroscopy DLTS technique. In addition the effect of the level of Be-doping concentration on the hole deep traps is investigated. It was observed that with increasing the Be-doping concentration from 1 X 1016 to 1 X 1017 cm-3 the number of detected electrically active defects decreases for samples grown on 311 A substrate whereas it increases for 100 orientated samples. The DLTS measurements also reveal that the activation energies of traps detected in 311 A are lower than those in 100 . From these findings it is expected that mobilities of 2DHGs in Be-doped GaAs-GaAlAs devices grown on 311 A should be higher than those on 100 . Introduction High index planes have attracted a great deal of attention for the production of high quality epitaxially grown semiconductor materials. In particular the incorporation of silicon as an amphoteric dopant in AlGaAs 1 2 and GaAs 3 grown on high index GaAs substrates have been studied extensively using Hall photoluminescence and photothermal ionisation measurements. Compared to silicon beryllium .
