To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
We have investigated by x-ray diffraction defect structures in 6H-SiC after neutron irradiation with different fluences and followed by different annealing procedures. An interpretation along a model of Klimanek [1, 4–6] shows, that higher fluences lead to a stronger than linear reduction of the correlation length, whereas higher annealing temperatures correlate with a better recovery of the correlation length. In addition defects of 1st kind created by irradiation are reduced by annealing. We find that annealing changes the character of the defects and it accentuates a defect structure already present in the original samples.
We report on experiments which observe on a microscopic scale the migration of isolated hydrogen in InP, GaAs, and InAs. Using the radioactive acceptor 117Cd, Cd-H pairs have been formed in these III-V semiconductors. After the decay of 117Cd to 117In, H is no longer bound to an acceptor and can diffuse freely. This diffusion has been observed by perturbed yy angular correlation (PAC) spectroscopy. At 10 K, the occupation of two different lattice sites by hydrogen has been observed. First results on the diffusion of hydrogen will be discussed.
The formation and properties of acceptor-hydrogen pairs in GaN have been studied using radioactive 111mCd acceptors and the perturbed γγ angular correlation spectroscopy (PAC). After H-loading by low energy implantation (100 eV) at temperatures between 295 K and 473 K, the formation of two Cd-H complexes involving about 30% of the Cd-acceptors is observed. The complexes have been identified as single hydrogen atoms bound to the Cd acceptor in two different configurations. The dissociation enthalpies of these configurations have been determined as 1.1(1) eV and 1.8(1) eV, respectively.
The characteristic life-times of radioactive isotopes can be used to label and identify defect levels in semiconductors which can be detected by photoluminescence (PL). This technique is illustrated with three examples: ZnS doped with radioactive 65Zn by neutron irradiation and GaAs doped with radioactive 111In by ion implantation. Finally we report that doping GaAs with radioactive 71As which decays to stable 71Ga can be used to create GaAs antisites in GaAs in a controlled way and to identify their levels.
Perturbed Angular Correlation (PAC) and Hall measurements were used to investigate the stability of the passivating Cd-H complex in GaAs after low energy H implantation (150 eV, 1014 cm−2) at 300 K. From the observed Cd-H pair formation and reduction of hole concentration it is deduced that about 10 % of the implanted H atoms form pairs with the Cd atoms. The influence of the dopant depth profile on the apparent stability in zero bias isochronal annealing experiments is reported. After H loading a reduction of carrier mobility is observed, which is stable up to about 400 K. The formation of Cd-H pairs after low energy H implantation into InP was studied by PAC. By measuring the fraction of pairs in an isochronal annealing experiment, the stability of the pairs is deduced yielding a dissociation energy of ED = 1.8 (1) eV.
Email your librarian or administrator to recommend adding this to your organisation's collection.