Magneto-optical studies of 2D hole Landau levels and screening of donor states in p-type modulation doped Ga0.5Al0.5As/GaAs interfaces

We investigated low-temperature photoluminescence from p-type Al1−xGaxAs/GaAs heterostructures subjected to a magnetic field directed perpendicularly to the interface. Two observed type of structure related to interface transitions were interpreted as free (H-band) and donor-bound (D-line) electron recombinations with 2D holes. Properties of both type of structure were explained basing on the results of detailed band-structure calculations. Magnetic field measurements enabled us to examine the binding energy of donor screened by 2D holes in parallel electric and magnetic fields.