  We investigate the holographic correspondence between (p+1)-dimensional
($0\le p\le 4$) SYM theories with 16 supercharges and superstring theories on
the near-horizon limit of Dp-brane backgrounds. Following an approach based on
the tunneling picture, we study Euclidean superstring semi-classically along
null geodesics which connect two points on the boundary of the spacetime. We
extend the analysis of hep-th/0308024 and study the fermionic sector of the
superstring. For $p\ne 3$, we do not have world-sheet supersymmetry, and the
energies of bosonic and fermionic fluctuations do not match. By interpreting
the superstring amplitudes as correlators of gauge theory operators with large
R-charge J, we obtain gauge theory two-point functions including those of
fermionic operators. Our approach yields results consistent with the previous
supergravity analysis for the D0-branes, including the subleading part in J.
Our prediction from holography is that the two-point functions for the
supergravity modes are power-law behaved, even for the non-conformal ($p\ne 3$)
SYM theories.
