New photoluminescence lines in Vanadium doped GaAs grown by MOVPE
We examined the electrical and optical properties of vanadium-doped GaAs grown by metalorganic vapour phase epitaxy using vanadium tetrachloride (VCl4) as a novel dopant source. Samples with various vanadium incorporations were investigated. All samples were n type. The electron concentration dependence on the VCl4 flow rate was established. At 15 K, by comparison with undoped layers grown in the same conditions, photoluminescence spectra of V-doped exhibited three new emission bands: at 1.41, 1 and 0.72 eV. The 1 and 0.72 eV band emissions were attributed to V 2þ and V 3þ intracenter emission, while the 1.41 eV band was suggested to be a donor-bound transition. The identity of the donor is tentatively attributed to a donor complex that associates vanadium to an arsenic vacancy. From Hall effect as function of temperature, the donor ionisation energy was estimated to be about 102 ^ 5 meV. q 2003 Elsevier Science Ltd. All rights reserved.
Semi-insulating III–v materials
A meeting on this aspect of semiconductor physics was held at Nottingham University on 14–16 April 1980. It was organised on behalf of the Solid State Subcommittee of The Institute of Physics in response to a considerable worldwide interest in semi-insulating GaAs and InP.
High‐purity GaAs and Cr‐doped GaAs epitaxial layers by MBE
Liquid‐nitrogen‐temperature Hall mobilities of about 105 000 cm2/V sec have been achieved in n‐type epitaxial layers grown by molecular beam epitaxy (MBE). The Hall mobility of the p‐type epitaxial layers at 78 °K was about 8440 cm2/V sec. The net donor concentration and the net acceptor concentrations for n‐type and p‐type epitaxial layers were about 4×1014 and 1×1014 cm−3, respectively. The compensation ratio in the n‐type epitaxial layers was about 0.4 as determined from the 78 °K electron mobility. Cr‐doped GaAs buffer layers for FET’s were grown in a substrate temperature range of 500–640 °C. Sheet resistances in excess of 109 Ω/ ⧠ were achieved when the substrate temperature during the growth was about 580 °C or higher. The amount of Cr that can be incorporated into the epitaxial layer showed a strong substrate temperature dependence.