Nanoscale semiconductor structures such as quantum wells

wires

and dots have stimulated great interest due to the predicted improvement in device performance.Many unique and fascinating properties have been demonstrated in semiconductor nanostructures.ZnO is a wide direct band gapⅡ-Ⅵ semiconductor material with a large exciton binding energy of 60meV at room temperature

more larger than the ionization energy at room temperature(26meV)

so ZnO is a suitable high efficient ultraviolet material

blue light emitters and detectors at room temperature even at higher temperature.ZnO quantum dots has unique photoelectric properties compared with the bulk material

especial used in UV laser devices filed related with its exciton characteristic.In theory

the larger of exciton bind energy at room temperature

the more easily to realize high efficient stimulated emission at room temperature.So three-dimensional confined nannocrystalline ZnO(or ZnO quan-tum dots) become the hope of high efficient quantum dots laser even nanolaser

and attract great deal of interests of scientists.Therefore

it is very important to study the ground state energy(binding energy) of exciton of ZnO quantum dots in theory.Recent years

many methods were used to prepare quantum dots material with different shape and size

some modern measure technology and instruments were utilized to study the properties of the quantum dots.Many theoretical models were used to research the quantum dots

for example

effective mass qpproximately(EMA)

tight binding approximately(TBA)

pseudo method(PM)

et al.The EMA method is a direct and most useful method for parabola energy band structure.In this paper

we calculate the ground state energy of exciton in ZnO quantum dots by variation method.The calculation is based on a new trial wave function under the effective mass approximation(EMA).The calculation is very simple for the simple trial wave function.Comparision of the calculation results with the experiment values indicates the new trial wave function is right.We also compared the calculation results with the Y.Kayanuma's calculation results.The compared results illuminate the two calculation results is very approach

that make out the new trial wave function is simple and effective

and can applied to other semiconductor quantum dots.