The phonon modes of a quantum well wire, formed by a cylindrical polar semi
conductor 1 (well material) (rho < R-1) embedded in another polar semicondu
ctor 2 (barrier material) (R-1 <less than or equal to> rho < R-2), were stu
died by using the dielectric continuum model. The confined longitudinal opt
ical phonon modes both in the wire (LO1) and in the barrier materials (LO2)
and the interface optical (IO) phonon modes as well as the corresponding e
lectron-phonon interaction Hamiltonians are derived. With a two-parameter v
ariational trial wave function, the bound-polaron binding energy has been c
alculated numerically for different confining potential heights and wire ra
dii. The result shows that the electron-phonon interaction can greatly modi
fy the impurity binding energy. The IO modes are the main factor contributi
ng to the modification. The influence of the LO1 modes increases as the wir
e radius increases and reaches the bulk limit at large wire radius, while t
he LO2 modes only show their influence at narrow wire radius.