Piezoelectric field measurements by photoreflectance in strained InGaAs/GaAs structures grown on polar substrates

• Published in: Microelectronics Vol. 26; no. 8; pp. 827 - 833
• Main Authors: Berger, P.D., Bru, C., Baltagi, Y., Benyattou, T., Berenguer, M., Guillot, G., Marcadet, X., Nagle, J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.1995
• ISSN: 1879-2391; 1879-2391
• DOI: 10.1016/0026-2692(95)00043-7

Photoreflectance (PR) measurements were performed on specific structures grown by molecular-beam epitaxy on different substrate orientations: 〈111〉B, 〈111〉B 2° off, 〈111〉A and 〈100〉. A strained In0.2Ga0.8As quantum well was grown in the space charge layer of an undoped GaAs layer. On a polar substrate orientation 〈111〉, the strain-induced piezoelectric field in the quantum well modifies the field in the space charge layer. PR spectra recorded in such structures exhibit Franz Keldysh oscillations from which we can measure the internal electric field. The piezoelectric field is then deduced from a comparison between two structures differing only by the presence of the strained quantum well. Experimental values ranged between 110 kV/cm and 150 kV/cm, and were used to determine experimentally the piezoelectric constant e14 in In0.2Ga0.8As.