Intrinsic Concentrations are different in some books. Why?

[birkan93]

Homework Statement

Solid State Physics

Relevant Equations

Intrinsic Concentration

instinct concentration temperature relationship formula?
in some books, Si instrinct concentration(ni)=1,1x10^10cm-3, some books instrinct concentration(ni)=1,5x10^10cm-3. Why these values are different?

 

[Lord Jestocost]

Maybe, this paper might be of help:
A. B. Sproul, M. A. Green, and J. Zhao, Improved value for the silicon intrinsic carrier concentration at 300 K , Appl. Phys. Lett. 57, 255 (1990)

Abstract

A recent review suggests that the commonly cited value of 1.45×10¹⁰ cm⁻³ for the silicon intrinsic carrier concentration at 300 K is inconsistent with the best experimental and theoretical results. An alternative value of 1.08×10¹⁰ cm⁻³ was suggested. A new experimental measurement of 1.01×10¹⁰ cm⁻³ is reported with an estimated one standard deviation uncertainty of only 3%. This appears to be the most accurate experimental determination of this parameter at any temperature.