The main characteristics of the depletion layer, are obtained on the basis of a suggested model, according to which, the charge is distributed, not as a space charge but as surface charge on the lateral sides of the depletion layer. Comparative discussions of the results obtained according to both models are given. The dependences on the ratio ?? ?? and the applied voltage ?? ?? are clarified. Both forward and backward biases are also considered. Graphical representations for the obtained relations, considering an illustrative example on a silicon cell are also given.