ISSN:
1662-0356
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Natural Sciences in General
,
Technology
Notes:
Deep-level defects related with 5d transition metal, osmium (Os) have been studied in ntypeGaAs. Os has been incorporated in epitaxial n-GaAs layers in situ, during growth by lowpressuremetal-organic chemical vapour phase epitaxy (MOVPE) technique. Mesa p+nn+ junctiondiodes are fabricated for investigations by deep level transient spectroscopy (DLTS). Two deeplevelpeaks, observed in majority carrier (electron) emission spectra, Os1 and Os2, show asignificant shift in peak positions to lower temperatures with the applied junction reverse bias,demonstrating enhancement of the thermal emission rate by the junction electric field. DoublecorrelationDLTS (DDLTS) measurements have been employed for accurate quantitativeinvestigations of the observed field dependence. However, in view of the relatively smallconcentration of the deep level Os1, this technique is found to yield reliable data only for the deeplevel corresponding to the dominant peak, Os2. Detailed data have been obtained on the field effectfor Os2, extending over junction electric field values 3 x 106 V/m - 1.2 x 107 V/m. The measuredemission rate signatures show a reduction of the thermal activation energy from 0.48 eV to 0.21 eVfor Os2 over this electric field range. Analysis of the data in terms of the recent theoretical work onfield dependence indicates that Os2 is associated with a substitutional Os donor
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/42/transtech_doi~10.4028%252Fwww.scientific.net%252FAST.46.73.pdf
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