Characteristic of P-type AlAs/GaAs Bragg Mirrors Grown by MBE on (۱۰۰) and (۳۱۱)A Oriented Substrates

P-type GaAs/AlAs distributed Bragg mirrors have been grown using molecular beam epitaxy on (۱۰۰) and (۳۱۱)A GaAs substrates in a similar conditions. A comparison of I-V measurements shows that the resistance of the ungraded mirrors grown on the (۳۱۱)A substrate is ۳۵ times lower than those grown on the (۱۰۰) substrate with similar structure. The effective barrier heights for both (۳۱۱ )A and (۱۰۰) barriers were extracted from their Arrhenius behaviour, obtained from their current temperature dependence. The calculated values for (۳۱۱)A and (۱۰۰) effective barrier heights are ۱۴۱ meV and ۳۴۱ meV, respectively. The room temperature values of the specific differential resistance for both devices around zero bias [i.e. Rc=(dV/dJ)Iv=۰] were calculated. The approximated values for (۳۱۱)A and (۱۰۰) devices are ۸۰ mW-cm۲ and ۲.۸mW-cm۲ respectively.  

Keywords:

AlAs , GaAs , DBR , Substrate Orientation , VCSEL