Fermi level movement for n- and p-GaAs interfaces: Effects of temperature and dopant concentration

Photoemission studies demonstrate that temperature and dopant concentration dependent movement of the surface Fermi level is controlled by coupling between adatom-induced and bulk states. At a low temperature for lightly doped n- or p-GaAs, initial band bending inhibits tunneling and EF remains near the band edges until the onset of metallicity. For heavy doping, greater band bending reflects a thinner depletion region. Thermal cycling for 20≤T≤300 K for low coverages demonstrates that band bending is reversible.