Synthesis and Luminescence Study of Mn-doped Nanosized Al2O3

Mn
³
+-doped Al
₂
O
₃
was obtained by combustion method. It was found that the resulting powder, with particle sizes of 10-70 nm, consists of a mixture of transition aluminas (δ
^*
, δ, θ), among which δ
^*
-polymorph is dominant. The presence of Mn
³
+ ions results in a wide absorption band in the 400-620 nm region, but no emission of these ions was observed, probably due to a strong Jahn-Teller effect. It is shown that a part of Mn impurity ions exists in the oxidation state +2 and occupies tetrahedral positions in the δ*-Al
₂
O
₃
, causing a broad emission band with a maximum at 520 nm.