已知函数\(f(x)=(x-2)e^{x}\)．
\((1)\)求函数\(f(x)\)的单调增区间；
\((2)\)设\(g(x)=f(x)+2e^{x}-ax^{2}\)，\(h(x)=x\)，若\([g(x_{1})-h(x_{1})]⋅[g(x_{2})-h(x_{2})] > 0\)，对任意\(x_{1}\)，\(x_{2}∈(0,+∞)\)成立，求实数\(a\)的取值范围．