Improved open circuit voltage using metal mediated epitaxial growth in thyristor structure solar cells

Most presently manufactured bulk photovoltatic devices suffer from poor rea r surface recombination velocities which limit the achievable efficiencies. In order to overcome this efficiency limitation, an innovative approach to redesigning the rear contract has been sought. The Buried Contract Solar C ell (BCSC) has been chosen as the basis for this study as this technology h as been proven to be superior in performance to other commercially availabl e bulk technologies. The new rear contracting scheme has been devised with improves experimental devices demonstrated. It utilises a process known as Metal Mediated Epitaxial Growth (MMEG) to achieve an improves Back Surface Field (BSF). This design device can also take advantage of the thyristor st ructure by utilising the p(+) region formed by MMEG in conjunction with the n-p-n structure unavoidably produced during most manufacturing processes. Results indicate that superior rear surface passivation can be achieved usi ng this process and design. Higher open circuit voltages in the vicinity of 30-49 mV have been achieved relative to the conventional BCSC, indicating that higher efficiency devices are possible. Copyright (C) 2000 John Wiley & Sons, Ltd.