Study of Phosphorus-Based Compound Semiconductors Grown by Solid Source Molecular Beam Epitaxy

• Main Authors: Yi-Cheng Cheng, 程一誠
• Other Authors: Sien Chi
• Format: Others
• Language: en_US
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/21821255396485398170

博士 === 國立交通大學 === 光電工程所 === 89 === Recent researches on semiconductors have been focusing on III-V phosphides due to their potential optoelectronic applications in the visible and high-speed devices. This thesis studies In0.5(GaxAl1-x)0.5P (x=0~1) thin films lattice-matched to GaAs substrates and different heterostructures grown by all solid source molecular beam epitaxy (SSMBE) over the entire alloys. By precisely controlling the three-zone valved phosphorus cracker cell, the optoelectronic properties of the In0.5(GaxAl1-x)0.5P epilayers grown were investigated. The temperature dependent photoluminescence and photoreflectance showed that the ordering effect and the energy gap of InGaP epilayers decreased as the cracker temperature increased. Contradict to the results reported in the Metal-Organic Chemical Vapor Deposition (MOCVD) growth, the incorporation efficiency of both donor (Si) and acceptor (Be) showed no apparent variation while changing the substrate misorientation. The dependence of Si doping efficiency in the InGaAlP epilayers on the cracker temperature and the growth temperature was also studied. Since the cracker temperature changes mainly the P4/P2 flux ratio, the enhancement of the effective carrier concentration in Si-doped InGaAlP with higher P4/P2 flux ratio is attributed to the reduction of oxygen contamination. A strong phase separation can be induced in the growth of (InP)2/(GaP)2 short-period superlattices (SPS), which if inserted in a general quantum well structure can form a quantum-wire like heterostructure. Most importantly, an alterable temperature dependent wavelength shift was observed in the SPS structure growth, which can be changed if the growth interruption was adjusted. A larger substrate tilt angle can suppress the lateral composition modulation in (InP)/(GaP) heterostructures. The observed high quality phosphide epilayers suggests that the SSMBE system is reliable and useful for many practical applications.