晶格失配对InAsxP1-x/InP发光特性的影响

Lattice Mismatch Effect on Photoluminescence from InAs_xP_(1-x)/InP Heterostructuer

采用低压金属有机化学气相沉积(LP-MOCVD)技术,在掺Fe的半绝缘InP衬底上制备了InAs0.157P0.843外延层。利用变温光致发光研究了InAs0.157P0.843外延层在13～300K温度范围内的发光特性,通过理论分析与计算,证实了在应力作用下InAs0.157P0.843外延层价带顶的轻重空穴带发生了劈裂,并研究了导带底与价带顶轻空穴带之间形成的复合发光峰在应力作用下随温度的变化规律。

The variable-temperature photoluminescence spectra of strained InAsxP1 _x/InP heterostructuer were experimentally determined in the temperature range 13 -300 K. A theoretical calculation was presented that takes into account the temperature-induced variations in band gap and biaxial strain to explain the PL spectra. The results showed that strain which is induced by lattice mismatch between epitaxial layer and substrate removes the degeneracy between the light- and heavy-hole states at the top of the valence band, and with temperature under 100 K, the recombinations from the conduction band to the split valence bands are both observed in the photoluminescence spectra. As temperature is raised,it results in an increasingly larger lighthole population than that of heavy-hole due to thermalization, so when temperature is beyond 100 K only the recombination from the conduction band to the light-hole state can be observed. We also find that the energy of the recombination between the conduction band and the light-hole and heavy-hole state changes as a function of temperature.