Electron mobility and free-carrier absorption in GaAs: Determination of the compensation ratio

• Published in: Journal of applied physics 1979-02, Vol.50 (2), p.899-908
• Main Authors: Walukiewicz, W, Lagowski, L, Jastrzebski, L, Lichtensteiger, M, Gatos, H C
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.326008

Theoretical calculations of electron mobility and free-carrier absorption in n-type GaAs at room temperature were carried out taking into consideration all major scattering processes. It was found that satisfactory agreement between theoretical and experimental results on free-carrier absorption is obtained only when the effect of compensation is quantitatively taken into account. In conjunction with experimental studies it is shown that the electron mobility (for n≳1015 cm−3) and free-carrier absorption (for n≳1016 cm−3) are sufficiently sensitive to the ionized impurity concentration to provide a reliable means for determining the compensation ratio. Convenient procedures are presented for the determination of the compensation ratio from the free-carrier absorption coefficient and from the computed values of room-temperature electron mobility. Values of the compensation ratio obtained by these two procedures are in good agreement provided the carrier-concentration variations in the material are not appreciably greater than 10%.