THERMIONIC ESCAPE STUDY IN p-i-n InP/InAs53P47 MULTI-QUANTUM WELL SOLAR CELL

Charge carriers thermal activation energies are obtained from the Arrhenius plot of photoluminescence vs. temperature intensity measurements made on InP/InAs53P47 multiquantum well solar cells. A theoretical investigation consisting of band structure calculation was undertaken in order to determine the height of the effective potential barriers seen by photo-carriers created in the InAs53P47 quantum wells. A very good agreement is found between experimentally obtained activation energies and theoretically determined effective potential barriers. These results infer that light holes thermionic escape drives the PL intensity decrease at lower temperatures. For an intermediate temperature range, a PL activation energy corresponding to the difference in effective confining potential barrier between heavy holes and light holes is obtained. At higher temperatures, the PL extinction process is dominated by direct heavy-hole escape. These results offer some insights for better designs of photovoltaic quantum confined devices.