Structural and optical quality of GaN/metal/Si heterostructures fabricatedby excimer laser lift-off

Gallium nitride (GaN) thin films grown on sapphire substrates were successf ully bonded and transferred onto Si substrates using a Pd-In metallic bond. After bonding, a single 600 mJ/cm(2), 38 ns KrF (248 nm) excimer laser pul se was directed through the transparent sapphire followed by a low-temperat ure heat treatment to remove the substrate. Channeling-Rutherford backscatt ering measurements revealed the thickness of the defective interfacial regi on to be approximately 350 nm. The full width at half maximum, low-temperat ure (4 K), donor-bound exciton photoluminescence (PL) peak was larger by 25 % on the exposed interfacial layer compared to the original GaN surface. Io n milling of the exposed interface to a depth of 400 nm was found to remove the interfacial layer and associated defects. The minimum channeling yield and PL linewidths from the exposed interface were found to be comparable t o those obtained from the original GaN surface after ion milling. (C) 1999 American Institute of Physics. [S0003-6951(99)04539-8].