| Growing on (111) oriented substrate has been long attracted much attentions due to the presence of piezoelectric field when the material is under strain. However, growing on this orientation still poses a great challenge to crystal grower due to the tendency of forming pyramidal facets along the ⟨110⟩ directions. This dissertation covers the optimization of the growth on (111) GaAs and (111) InP substrates using molecular beam epitaxy. The enhancement of the material performance due to the piezoelectric effects was also investigated in this dissertation.; Growing on (111)A surface is very difficult due to the fact that the surface is terminated with group III atoms. On this surface, Si can either occupy the group III site, becomes a donor, or the group V site, becomes an acceptor, depending on the growth condition. Also, the group III terminated surface makes the epi-layer grown on (111)A substrates metal-rich under most of the growth conditions. Therefore, a high quality material is hard to obtain on (111)A surface. Whereas, growing on (111)B surface, Si always acts as a donor. High quality epi-layer can be achieved by employing high growth temperature, low V/III ratio and misoriented substrate.; High quality AlGaAs/GaAs heterostructure has been grown on (111)B GaAs substrates. Two-dimensional electron gas (2DEG) Hall mobility of 7,200 cm 2/Vs with sheet density of 7.7 × 1011 cm −2 with a 134 Å spacer layer at room temperature, and 90,000 cm2/Vs with sheet density of 6.2 × 1011 cm−2 at 77K have been achieved on (111)B GaAs. Excellent material has also been grown on (111)B InP. InAlAs/InGaAs heterostructure grown on (111)B InP gave a room temperature 2DEG Hall mobility of 11,200 cm 2/VS with sheet density of 3.0 × 1012 cm −2 with a 40 Å spacer layer. At 77K, the 2DEG Hall mobility was 42,800 cm2/Vs with sheet density of 2.3 × 1012 cm−2. This heterostructure showed a 30% enhancement in 2DEG sheet density due to the piezoelectric effects.; Excellent material has been grown on (111) surface using molecular beam epitaxy. This dissertation covers the optimal growth condition of (111)B GaAs and (111)B InP. With electrostatic analysis plus semiempirical approach, a simple equation for estimating the 2DEG sheet density is also presented in this dissertation. |
