Photoluminescence Spectroscopy of 4H- and 6H-SiC

Author

William A. Davis

Date of Award

12-1994

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

Robert L. Hengehold, PhD

Abstract

Typical undoped bulk grown SiC shows n- or p-type conductivity due to residual impurities such as nitrogen, boron, or aluminum. In order to produce high resistivity material, vanadium can be used as a compensating dopant. Since vanadium is an amphoteric dopant in SiC, it produces either a donor state, V_Si⁴⁺(3d¹) → V_Si⁵⁺(3d⁰), or an acceptor state, V_Si⁴⁺(3d¹) → V_Si³⁺(3d²). Thus, vanadium doping can compensate both n- and p-type conductivity. In this work, vanadium doped and undoped 4H- and 6H-SiC grown by the sublimation method have been studied using low temperature photoluminescence (PL). It was found that the luminescence observed between 0.85 to 0.95 eV of the intra-3d-shell transition of V_Si⁴⁺(3d¹) increased by an order of magnitude in samples intentionally doped with vanadium compared to samples unintentionally doped. In addition, the dominant visible-region luminescence was attributed to titanium which is an isoelectronic trap in SiC. The presence of a broad peak centered at approx. 1.90 eV in some samples is believed to be attributed to donor-acceptor pair recombination between a Ti_Si-N_c complex donor and the boron defect complex acting as an acceptor. Finally, the Ti_Si-N_c complex donor location in the bandgap of 6H-SiC is estimated to be E_c-0.54 eV.

AFIT Designator

AFIT-GAP-ENP-94D-02

DTIC Accession Number

ADA289326

Recommended Citation

Davis, William A., "Photoluminescence Spectroscopy of 4H- and 6H-SiC" (1994). Theses and Dissertations. 6360.
https://scholar.afit.edu/etd/6360