Deep level study of Mg-doped GaN using deep level transient spectroscopy and minority carrier transient spectroscopy
2016 (English)In: Physical Review B, ISSN 2469-9950 (print); 2469-9969 (online), Vol. 94, no 4, 045206Article in journal (Refereed) Published
Deep levels in Mg doped GaN have been studied using deep level transient spectroscopyand minority charge carrier transient spectroscopy. Two traps are revealed in the investigatedtemperature range. In the substrate, one electron trap labelled ET1 (EC – 0.158 eV) is observedand in the Mg-doped layer, one hole trap labelled HT1 has been revealed. By varying theelectric field, it is found that the hole trap HT1 exhibits an electric field enhanced hole emissionrate. Using four theoretical models based on 3-dimensional Coulombic Poole-Frenkel effect, 3-dimensional square well Poole-Frenkel effect, phonon assisted tunneling, and 1-dimensionalCoulombic Poole-Frenkel effect including phonon assisted tunneling, the experimental data arefitted in order to justify the field enhanced emission process. It is found that the 1-dimensionalCoulombic Poole-Frenkel model including phonon assisted tunneling is consistent with theexperimental data. Since the trap exhibits Poole-Frenkel effect, we suggest it is acceptor like.From the theoretical model, the zero field activation energy of HT1 and an estimate of the holecapture cross section have been determined as Ev+0.57 eV and 1.9x10-15 cm2, respectively.Since the level is only observed in Mg-doped material, it is suggested that the trap can beassociated with a Mg related defect.
Place, publisher, year, edition, pages
AMER PHYSICAL SOC , 2016. Vol. 94, no 4, 045206
IdentifiersURN: urn:nbn:se:liu:diva-121705DOI: 10.1103/PhysRevB.94.045206ISI: 000381484500007OAI: oai:DiVA.org:liu-121705DiVA: diva2:858370
Funding agenices: Swedish Research Council [621-2010-3850]; Swedish Energy Agency [38338-1]
Vid tiden för disputation förelåg publikationen endast som manuskript2015-10-022015-10-022016-09-26Bibliographically approved