ELASTIC-MODULI OF GALLIUM NITRIDE

The second-order elastic constants of wurtzite phase GaN have been mea sured with 0.2% accuracy using a resonance ultrasound method. The meas urements were done on a 0.29-mm-thick GaN crystal grown by chloride va por-phase transport and subsequently detached from the substrate. The elastic moduli in units of GPa are: c(11) = 377, c(12) = 160, c(13) = 114, c(33) = 209, and c(44) = 81.4. The elastic moduli are used to cal culate the biaxial misfit stresses expected in heteroepitaxial thin fi lms of GaN. (C) 1997 American Institute of Physics.