ZnTe PN homojunctions were fabricated using thermal diffusion of Al into a ZnTe film grown on lattice-matched GaSb substrates by molecular beam epitaxy. Rectifying J-V characteristics and the photovoltaic effect were observed which suggested that n-type ZnTe was successfully achieved. The reverse bias breakdown voltage was found to be dependent on annealing condition and acceptor concentration, and the trend agreed with PN junction theory. Secondary ion mass spectrometer depth profiles of the Al film showed that Zn and Te out-diffused into the Al film during annealing. This out-diffusion was undesirable because it might result in Zn vacancies which compensated Al donor atoms. Photoluminescence measurements of annealed ZnTe samples without the Al diffusion layer showed strong band-edge luminescence at room temperature. Mid-gap luminescence also appeared for annealed samples but the intensity was lower than the band-edge peak. This technique might lead to a better understanding of the n-type doping problem for ZnTe, and could lead to in-situ doping techniques and treatments.

Aluminum Diffusion in ZnTe Films Grown on GaSb Substrates for n-Type Doping. M.J.DiNezza, Q.Zhang, D.Ding, J.Fan, X.Liu, J.K.Furdyna, Y.H.Zhang: Physica Status Solidi C, 2012, 9[8-9], 1720-3

Table 39

Thermal Diffusivity of Al in ZnTeS