Electrical characterization of a buried GaSb p-n junction controlled by native defects

• Published in: Crystal research and technology (1979) 2014-08, Vol.49 (8), p.628-633
• Main Authors: Gorni, M., Parisini, A., Gombia, E., Baldini, M., Vantaggio, S., Ghezzi, C.
• Format: Article
• Language: English
• Subjects: Crystal defects; Crystals; Diffusion; Formations; GaAs/GaSb; Gallium arsenide; Gallium arsenides; MOVPE; P-n junctions; Solar cells; TPV; Zinc; Zn diffusion
• ISSN: 0232-1300; 1521-4079
• DOI: 10.1002/crat.201300411

Buried GaSb junctions were induced in Te‐doped GaSb bulk crystals by growing a heavily Zn‐doped GaAs layer on GaSb. However, the p‐n junction resulted to be located much more deeply with respect to the Zn diffusion front and originated by a local rising up of native acceptor density, which controls the p‐type conductivity conversion of the GaSb substrate for about 1 μm beyond the Zn penetration depth. Admittance spectroscopy measurements supported the identification of such defects with the double native acceptor GaSb. Current‐voltage characteristics of the p‐n junction, performed after the removal of the GaAs layer, were here analyzed as a function of the temperature for different Zn doping levels and resulted consistent with the model previously proposed to explain the formation of the junctions. Thanks to its absorption properties, GaSb is one of the best candidates for TPV and 3rd gen PV applications. A buried GaSb junction in a GaAs/GaSb heterostructure has been obtained by growing a heavily Zn doped GaAs epitaxial layer on a n‐type GaSb substrate, where Zn impurities diffuse. Current‐voltage characteristics show interesting rectification properties, however the formation of the junction resulted to be mainly controlled by an enhancement of the native defect GaSb rather than Zn.