InGaAsN的MBE外延生长技术及太阳能电池.pptx

InGaAsN的MBE外延生长技术及太阳能电池制作李景灵李景灵 林云昊林云昊 周仕忠周仕忠 背景InGaP/InGaAs/Ge 三结太阳能电池技术已成熟；提出基于GaAs体系 InGaP/GaAs/x/Ge四结电池材料；新材料的禁带宽度要求：0.951.05eV；InGaAsN材料禁带宽度可在上述范围调整因此：X=InGaAsNX=InGaAsN已知该四结太阳能电池效率值已达43%InGaAsN的MBE生长技术关键技术：N的复合，使得器件的光学和电学性能下降；高质量的InGaAsN薄膜，是从减少N元素对其性能的影响着手的。一般InGaAsN太阳能电池薄膜中N含量不超过2%InGaAsN薄膜优化生长生长温度要低：多数MBE生长方式均在430-500；后退火工艺 低温生长低温生长可以降低受主浓度（降低N对薄膜的消极影响）Acceptor concentration（measured by CV）vs substrate temperature for GaInNAs epilayers and solar cells.A general trend of decreasing acceptor concentration with decreasing substrate temperature is observed后退火工艺可改善晶体质量，提高外量子效率可减少N对薄膜的消极影响，明显提高短路电流密度；J-V characteristics of the InGaAsN DHJSCs under AM 1.5 G illuminationwithout and with post-thermal annealingComparison of the quantum efficiency of the InGaAsN DHJSCs without andwith post-thermal annealing太阳能电池制作工艺利用晶片键合的方法,将基于倒置结构生长的GaInP/GaAs/InGaAs三结太阳和Ge太阳电池单片集成,充分利用Ge电池,既直接作为四结电池的底电池,又作为支撑衬底,实现四结带隙能量分别为1.9/1.4/1.0/0.67eV的太阳电池太阳能电池制作工艺亮点亮点：引入Sb：降低band gap，提高lattice constant于rf-plasma nitrogen sources前方安装偏移盘(Biased deflection plates)太阳能电池制作工艺 太阳能电池制作工艺Sample1：GaInNAs(without the use of deflection plates)Sample2：GaInNAs(DP)(grown using deflection plates)Sample3：GaInNAsSb(grown using biased deflection plates)The use of deflection plates has increased the IQE of the GaInNAs cell from 56%to 68%at maximum.The addition of antimony drives the device IQE even higher,reaching 79%at maximum.The absorption edges of the materials closely correspond to the band gaps as measured by PL:GaInNAs,1.08 eV;GaInNAs（DP）,1.03 eV;and GaInNAsSb,0.92 eV.太阳能电池制作工艺（少子寿命少子寿命）GaInNAs film：0.55 nsGaInNAs（DP）film：0.74 ns.GaInNAsSb：0.20 ns 太阳能电池制作工艺太阳能电池制作工艺太阳能电池制作工艺The QEs for the samples with the wide depletion widths are the best reported for a GaInNAs sample,0.96.A report by Li et al on GaInNAs samples with similar bandgaps,but grown by MOCVD,shows maximum QEs below 0.7.Indeed,the best GaInNAs solar cells reported anywhere have had near band-edge QEs of approximately 0.8.