Experimental Investigation On The Fabrication Of GaSb Cell And The Mechanism Of Zinc Diffusion In N-GaSb

Based on investigation of manufacturing technology of silicon cell as well as technical uniqueness in fabricating GaSb cells (such as vapor diffusion and removing the heavy diffusion layer), we set forth a complete procedure of manufacturing the GaSb cell.The p-n junction is central to a photovoltaic (PV) cell, so its formation is the most important and basic part in manufacturing the PV cell. To form the p-n junction, we apply a "pseudo-closed" technique in gas to diffusing group II element zinc into N-GaSb doped with group VI element tellurium. For the Zn diffusion into N-GaSb, we set up an experimental system, including such subsystems as the pseudo-closed box,the tubing system for gas,heating systems and so on.The diffusive process of Zn into N-GaSb has been investigated experimentally and numerically. In the experiment, the pure Zn and Sb are used as diffusion source. After the diffusion has been completed for different durations and working temperatures, the final distributions of Zn in depth are measured by SIMS (Secondary Ion Mass Spectrometry), and the influences of the initial number of Zn particles are also checked on both SIMS measurement and Zn final distribution in depth. The initial amount of Zn particles is found to be critical, and the experiment conditions for acceptable Zn diffusion profile are figured out. The corresponding internal quantum efficiencies for different Zn distributions are predicted and the efficiency can reach up to 70% as long as the chemical etching is extremely precise.