Aluminum oxides and hydroxides (Al2O3, Al(OH)3 and AlOOH) are extremely difficult to differentiate by XPS. A compilation of Al 2p3/2 values and modified Auger parameter values (Al 2p - KL23L23(1D)) are presented below. Unfortunately, statistical speaking, the values for the varying oxides and hydroxides overlap each other.
Table 1. Al 2p3/2 binding energy values [1].

Table 2. Al 2p-KL23L23(1D) modified Auger Parameter values [1].

[1] C.D. Wagner, A.V. Naumkin, A. Kraut-Vass, J.W. Allison, C.J. Powell, J.R.Jr. Rumble, NIST Standard Reference Database 20, Version 3.4 (web version) (http:/ 2003.