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Báo cáo hóa học: " Electrical characterisation of deep level defects in Be-doped AlGaAs grown on (100) and (311)A GaAs substrates by MBE"

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 www.nanoscalereslett.eom 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 Altt29Ga0.71As 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 .