TY - JOUR
T1 - Optical characterization of bulk GaN grown by a Na-Ga melt technique
AU - Skromme, B. J.
AU - Palle, K.
AU - Poweleit, C. D.
AU - Yamane, H.
AU - Aoki, M.
AU - DiSalvo, F. J.
N1 - Funding Information:
This work was supported by the Office of Naval Research Multidisciplinary University Research Initiative on III-Nitride Crystal Growth and Wafering, Grant No. N00014-01-1-0716, monitored by Dr. C.E.C. Wood. The ASU portion of this work was also supported by the Materials Research Science and Engineering Center at ASU, under Grant No. DMR 96-32635 from the National Science Foundation.
PY - 2002/12/16
Y1 - 2002/12/16
N2 - Colorless platelet and prismatic GaN crystals grown from a Na-Ga melt are characterized using room and low temperature photoluminescence (PL), reflectance, and micro-Raman scattering. The largest (∼ 3-4 mm) platelet shows a neutral donor-bound exciton (D0,X) PL peak with a full-width at half-maximum (FWHM) of 2.2 meV at 1.7 K. Raman scattering reveals an A1(LO) phonon mode in this sample at 739 cm-1, implying a free electron concentration (n) around 2-3 × 1017 cm-3. Smaller platelets grown in a pyrolytic BN crucible show even sharper exciton peaks, down to 0.22 meV FWHM. The stronger A1(LO) Raman peak lies at 733 cm-1 in this case, virtually unshifted by plasmon interactions. This observation implies n is in the mid 1016 cm-3 range or below. Residual Zn acceptors are frequently observed, and two-electron transitions identify the binding energy of the residual donor species as 33.6 meV, which may be ON. The 2.2 eV yellow PL band is generally weak or absent. The high purity and excellent optical properties may be due to gettering of donors such as O by the Na in the melt.
AB - Colorless platelet and prismatic GaN crystals grown from a Na-Ga melt are characterized using room and low temperature photoluminescence (PL), reflectance, and micro-Raman scattering. The largest (∼ 3-4 mm) platelet shows a neutral donor-bound exciton (D0,X) PL peak with a full-width at half-maximum (FWHM) of 2.2 meV at 1.7 K. Raman scattering reveals an A1(LO) phonon mode in this sample at 739 cm-1, implying a free electron concentration (n) around 2-3 × 1017 cm-3. Smaller platelets grown in a pyrolytic BN crucible show even sharper exciton peaks, down to 0.22 meV FWHM. The stronger A1(LO) Raman peak lies at 733 cm-1 in this case, virtually unshifted by plasmon interactions. This observation implies n is in the mid 1016 cm-3 range or below. Residual Zn acceptors are frequently observed, and two-electron transitions identify the binding energy of the residual donor species as 33.6 meV, which may be ON. The 2.2 eV yellow PL band is generally weak or absent. The high purity and excellent optical properties may be due to gettering of donors such as O by the Na in the melt.
KW - A1. Impurities
KW - A1. Optical characterization
KW - A2. Growth from solutions
KW - A2. Single crystal growth
KW - B1. Nitrides
KW - B2. Semiconducting III-V materials
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U2 - 10.1016/S0022-0248(02)01754-2
DO - 10.1016/S0022-0248(02)01754-2
M3 - Conference article
AN - SCOPUS:0037121693
SN - 0022-0248
VL - 246
SP - 299
EP - 306
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
IS - 3-4
T2 - BNS 2002
Y2 - 18 May 2002 through 23 May 2002
ER -