Le Journal de Physique IV 03 (1993) C5-315-C5-318
Experimental evidence of exciton wavefunction shrinkage in InxGa1-xAs/InP multi quantum wellsB. ROTELLI1, C. ARENA1, L. TARRICONE1 and C. RIGO2
1 Dipartimento di Fisica, viale delle Scienze, 43100 Parma, Italy
2 CSELT, via G. Reiss Romoli 274, 10184 Torino, Italy
We have studied the confinement effect on the ground state of the n=1 heavy exciton in InxGa1-xAs/InP Multi Quantum Wells (MQW) grown by Chemical Beam Epitaxy (CBE). Absorption optical spectra obtained in the excitonic region on several MQW were analyzed as a function of the well thickness Lz, ranging in the interval 25-80 Å, and as a function of the temperature (8-300 K). In agreement with the theory, a clear enhancement of the oscillator strength calculated by the integrated area of the heavy exciton absorption peak with the well thickness decrease, has been observed ; such increase is a direct evidence of the exciton wavefunction shrinkage and is one of the firstly reported in InxGa1-xAs/InP MQW. The ratio between 1s light and heavy exciton absorption area was used to evaluate their related reduced mass ratio µlh/µhh = 1.36±0.075 in excellent agreement with the calculated one (1.35).
© EDP Sciences 1993