This article concerns the fourth-order elliptic equations Delta(2)u - Delta u + lambda V(x)u = f (x, u), x (sic) R-N, u (sic) H-2(R-N), where lambda > 0 is a parameter, V (sic) C(R-N) and V-1(0) has nonempty interior. Under some mild assumptions, we establish the existence of nontrivial solutions. Moreover, the concentration of solutions is also explored on the set V-1(0) as lambda -> infinity.