P-Ga(1-x)InxAsyP1-y/InP材料的扩散长度测量

用激光扫描和电荧光衰减法测定了液相外延片p-Ga1-xInxAsyP1-y/InP(x=0.74,y=0.61)的少子扩散长度Im,并对这二种测试结果进行了比较,结果符合得很好。从这二种独立的实验结果获得表面复合速率S。S为6-7×104cm/s,扩散长度Lm为1.6～2.2μm。此外对p-Gε1-xInxAsyP1.y与InP衬底间的少数载流子行为进行了讨论。

MEASUREMENT OF DIFFUSION LENGTH FOR p-GalnAsP GROWN ON InP

The diffusion length of minority carriers in P-Ga(1-x)InxAsyP1-y(x=0.74,y=0.61)grown on InP substrate were determined by measuring the photocurrent under laser scan ard electroluminescent decay of the LED.The carrier concentration of the P-Ga(1-x)InxAsyP1-y,epitaxial layer is 2×1017cm3,while the layer thickness is 2~3nm.The photocurrent response R of the sample was measured as a function of distance(x)from the p-n junction(Fig.4),using a He-Ne laser with a wavelength of 6328A as the scanning light source.R is expressed as a function of the diffusion lengths(Ln),diffusion coefficients(Dn),surface recombination velocities(S)and photoabsorption coefficients(α).Csee Equation(1)]The electroluminescent decay method is somewhat indirect.The diffusion length(L)of the minority carriers is determined through the relation L=(Dτ)1/2,in which D is the known diffusion coefficient ard τ is the decay time of luminescence.The light emitting diodes were prepared with the samples used in the laser scan experiment.It was assumed that trapping lifetime has little influence on electroluminescence decay time.Experimental results of the two methods are ccmtrred in Table 1.The results show good agreement.The two independent experiments were analyzed simultaneously to obtain surface recombination velocity S.S is 6~7×104cm/s.Diffusion length L,is 1.6~2.2μm.Moreover,the behaviour of the minority carrier in P-Ga(1-x)InxAsyP1-yon InP substrate were discussed.