mocvd growth of high-quality delta-doped Al x Ga1−x As-GaAs structures

Metalorganic chemical vapor deposition has been used to form Si delta-doped structures of GaAs-Al_XGa_1−XAs, which have been characterized by mobility and sheet-carrier density measurements. At 20 K, mobility values of up to 300,000 cm²/V-sec, with carrier densities of ≈ 1×10¹² cm⁻², are reported. The mobility at 77 K is 131,000 cm²/V-sec. The Si delta-doped region has been imaged by cross-sectional transmission electron microscopy, and is seen to have a width of approximately 30 Å. Si delta doping in Al_XGa_1−XAs (x=0.23) has also resulted in high carrier levels, with an unexplained amphoteric behavior having been observed.