Journal of Materials Research

Invited Feature Papers

Growth and transport properties of p-type GaNBi alloys

Alejandro X. Levandera1, Sergei V. Novikova2, Zuzanna Liliental-Webera3, Roberto dos Reisa4, Jonathan D. Denlingera5, Junqiao Wua6, Oscar D. Dubona6, C.T. Foxona7, Kin M. Yua8 and Wladek Walukiewicza8 c1

a1 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720; and Department of Materials Science and Engineering, University of California, Berkeley, California 94720

a2 School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom

a3 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720

a4 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720; and Instituto de Física, UFRGS, Porto Alegre, RS 15051, 91501-970 Brazil

a5 Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720

a6 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720; and Department of Materials Science and Engineering, University of California, Berkeley, California 94720

a7 School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom

a8 Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720

Abstract

Thin films of GaNBi alloys with up to 12.5 at.% Bi were grown on sapphire using low-temperature molecular beam epitaxy. The low growth temperature and incorporation of Bi resulted in a morphology of nanocrystallites embedded in an amorphous matrix. The composition and optical absorption shift were found to depend strongly on the III:V ratio controlled by the Ga flux during growth. Increasing the incorporation of Bi resulted in an increase in conductivity of almost five orders of magnitude to 144 Ω-cm−1. Holes were determined to be the majority charge carriers indicating that the conductivity most likely results from a GaNBi-related phase. Soft x-ray emission and x-ray absorption spectroscopies were used to probe the modification of the nitrogen partial density of states due to Bi. The valence band edge was found to shift abruptly to the midgap position of GaN, whereas the conduction band edge shifted more gradually.

(Received August 09 2011)

(Accepted September 30 2011)

Key Words:

  • Semiconducting;
  • Nitride;
  • Bi

Correspondence:

c1 Address all correspondence to this author. e-mail: W_Walukiewicz@lbl.gov

Footnotes

This paper has been selected as an Invited Feature Paper.

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