Carrier localization in gallium nitride

Conference · Sun Sep 01 04:00:00 EDT 1996

OSTI ID:403973

Wetzel, C ^[1]; Walukiewicz, W ^[2]; Haller, E E ^[3]

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1. Lawrence Berkeley National Lab., CA (United States); California Univ., Berkeley, CA (United States)
2. Lawrence Berkeley National Lab., CA (United States)
3. Lawrence Berkeley National Lab., CA (United States); California Univ., Berkeley, CA (United States); and others

In wide bandgap GaN, a large number of interesting and important scientific questions remain to be answered. For example, the large free electron concentration reaching 10{sup 19} to 10{sup 20} cm{sup - 3} in nominally undoped material are ascribed to intrinsic defects because no chemical impurity has been found at such high concentrations. According to theoretical models, a nitrogen vacancy acts as a donor but its formation energy is very large in n-type materials, making this suggestion controversial. We have investigated the nature of this yet unidentified donor at large hydrostatic pressure. Results from infrared reflection and Raman scattering indicate strong evidence for localization of free carriers by large pressures. The carrier density is drastically decreased by two orders of magnitude between 20 and 30 GPa. Several techniques provide independent evidence for results in earlier reports and present the first quantitative analysis. A possible interpretation of this effect in terms of the resonant donor level is presented.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States); Ministry of Education, Science and Culture (Japan)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 403973
• Report Number(s): LBL--36937; CONF-9507172--4; ON: DE97000926; CNN: Grant 07505012; Grant 06452114
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARRIER DENSITY
CRYSTAL DEFECTS
GALLIUM NITRIDES
NITROGEN
VACANCIES
VERY HIGH PRESSURE