| Recent developments in semiconductor fabrication technology have generated interest in the use of semiconductor heterostructure devices. Despite the long history of semiconductor research, the ability to predict the characteristics of these devices has not been developed. The approximate analytical techniques used to analyze homostructures have been unable to quantitatively predict the behavior of heterostructures. This work overcomes the restrictions of these approximations though the use of numerical methods. This thesis describes the development and implementation of a numerical model that is applicable to the analysis of semiconductor heterostructures. In particular, the model is applied to the study of the n-N GaAs/Al(,x) Ga(,1-x) As isotype heterojunction. As a result of this work, guidelines for achieving high quality rectification in these structures are proposed. The model is also used to examine the viability of using a graded bandgap to improve the open circuit voltage performance of heterostructure solar cells. However, it was found that, although the improvement was possible, the overall device performance was superior if the grading was used to increase the collection efficiency rather than the open circuit voltage. |
