Vapor phase epitaxy growth of GaN on pulsed laser deposited ZnO buffer layer

Role of interfacial compound formation associated with the use of ZnO buffers layers in the hydride vapor phase epitaxy of GaN

“…Both AlN and ZnO films have been deposited onto the sapphire substrate and have led to improved nucleation and growth as reflected in a smoother surface morphology and improved materials properties. [10][11][12] In the case of ZnO, c-plane ZnO can provide a potentially improved lattice match over c-plane Al 2 O 3 . 13 The specific role of the ZnO buffer layer in the improvement of the GaN growth and materials properties is still unclear.…”

Microstructural compositional, and optical characterization of GaN grown by metal organic vapor phase epitaxy on ZnO epilayers

“…After optimization, the surface is homogeneous and free from obvious pit, pinhole, particle, cracking, or defect problems, which were reported by other groups. 4 This difference is probably due to epitaxy of the GaN on ZnO plus the lack of back etching under the optimized GaN / ZnO growth conditions. GaN overlayers.…”

“…GaN overlayers. 4,11 The ZnO layer also appears to act as a barrier for Al diffusing up from the c-Al 2 O 3 substrate. 12 It should be noted that the tails in the concentration profiles for Zn, Ga, and N, which extend into the c-Al 2 O 3 substrate, are probably artifacts due to residual particles of ZnO and GaN in the probe crater ͑visible in the inset SEM image of the analysis crater͒.…”

“…1 In spite of a smaller lattice mismatch ͑ϳ1.8% ͒, ZnO substrates have not been adopted because the NH 3 and H 2 carrier gases, used in conventional metal organic vapor phase epitaxy ͑MOVPE͒ growth of GaN, cause dissociation of ZnO at growth temperatures of about 650°C. [2][3][4] Recently, the authors reported on a novel lowertemperature approach to grow GaN by MOVPE on ZnO template layers without dissociation of ZnO so as to give continuous wurtzite ZnO and GaN layers with a smooth, welldefined interface. 5 In addition, subsequent lift-off of the GaN from insulating c-Al 2 O 3 substrates was demonstrated through preferential chemical etching of ZnO.…”

Properties of MOVPE GaN grown on ZnO deposited on Si(001) and Si(111) substrates

“…The similarity of GaN and ZnO in terms of energy gap, crystallographic structure and high thermal stability make them attractive candidates for heterostructures forming. GaN was grown epitaxialy on ZnO substrates [1,2] and ZnO layers were deposited on sapphire substrates by different techniques such as atomic layer epitaxy (ALE), pulsed laser deposition (PLD) or radio frequency (RF) sputtering but only very few groups have studied the growth of GaN on ZnO layer grown on silicon substrates [3][4][5][6].…”