INTRODUCTION
Over the past several years, there has been an increasing trend toward using metal pastes on p+ silicon surface as an emitter. Multiple applications have been proposed for these products such as bifacial solar cells [1]. This type of cell absorbs less infrared radiation therefore, the temperature of the cell stays lower than in monofacial cells. Furthermore, illumination of both the front and back side boosts the total efficiency of the cell [1]. Back contact solar cells [2] and n-type silicon solar cells [3], [4] are other potential applications. As an important advantage, n-type silicon has indicated a lower level of metal impurities than those present in typical silicon wafer products. This results in a higher minority carrier lifetime compared to p-type substrates [3], [4], [5]. It also has a much better lifetime stability compared to p-type when it is illuminated [6].