Group-III nitrides for optoelectronics

The research activities for wide-gap group-III nitrides cover the investigation of GaN films with nonpolar surfaces such as the M-plane, of group-III nitride heterostructures with particular emphasis on (In,Ga)N/GaN quantum wells, and of GaN-based nanostructures. All of these structures are grown by either plasma-assisted (N₂ based) or reactive (NH₃ based) MBE.

Heteroepitaxial growth

Since native bulk substrates are still not commercially available for any of the group-III nitrides, one is, in most cases, forced to retreat to the use of foreign substrates. The choice of the substrate depends strongly on the actual structure one desires to fabricate. In any case, nucleation, defect formation and residual strain have to be studied for each respective materials combination. The following substrates are routinely used in our research:

• planar growth, C-plane: Al₂O₃(0001), SiC(0001), GaN(0001), ZnO(0001)
• planar growth, M-plane: γ-LiAlO₂(100), SiC(1100)
• nanocolumn growth: Si(111)

For more information on specific subjects, click on one of the following links:

GaN with nonpolar surfaces

(In,Ga)N

Nanostructures