We study the nonlocal nonlinear problem $$\begin{aligned} \left\{ \begin{array}[c]{lll} (-\Delta )^s u = \lambda f(u) &{} \text{ in } \Omega , \\ u=0&{}\text{ on } \mathbb {R}^N{\setminus }\Omega , \quad (P_{\lambda }) \end{array} \right. \end{aligned}$$
(
-
Δ
)
s
u
=
λ
f
(
u
)
in
Ω
,
u
=
0
on
R
N
\
Ω
,
(
P
λ
)
where $$\Omega $$
Ω
is a bounded smooth domain in $$\mathbb {R}^N$$
R
N
, $$N>2s$$
N
>
2
s
, $$0<s<1$$
0
<
s
<
1
; $$f:\mathbb {R}\rightarrow [0,\infty )$$
f
:
R
→
[
0
,
∞
)
is a nonlinear continuous function such that $$f(0)=f(1)=0$$
f
(
0
)
=
f
(
1
)
=
0
and $$f(t)\sim |t|^{p-1}t$$
f
(
t
)
∼
|
t
|
p
-
1
t
as $$t\rightarrow 0^+$$
t
→
0
+
, with $$2<p+1<2^*_s$$
2
<
p
+
1
<
2
s
∗
; and $$\lambda $$
λ
is a positive parameter. We prove the existence of two nontrivial solutions $$u_{\lambda }$$
u
λ
and $$v_{\lambda }$$
v
λ
to ($$P_{\lambda }$$
P
λ
) such that $$0\le u_{\lambda }< v_{\lambda }\le 1$$
0
≤
u
λ
<
v
λ
≤
1
for all sufficiently large $$\lambda $$
λ
. The first solution $$u_{\lambda }$$
u
λ
is obtained by applying the Mountain Pass Theorem, whereas the second, $$v_{\lambda }$$
v
λ
, via the sub- and super-solution method. We point out that our results hold regardless of the behavior of the nonlinearity f at infinity. In addition, we obtain that these solutions belong to $$L^{\infty }(\Omega )$$
L
∞
(
Ω
)
.