Chuanbing Xiong

The influence of Si-doping to the growth rate and yellow luminescence of GaN grown by MOCVD

The growth of Si-doped GaN films was performed by MOCVD using a homemade reactor operating at atmospheric pressure on (0 0 0 1) oriented sapphire. A study of the effect of Si-doping indicated that the intensity of yellow band emission in GaN : Si films decreased with the increasing of SiH4/TMGa ratio, and it was largely influenced by the parasitic reactions in the gas phase. The yellow band intensity was depressed when the parasitic reactions were reduced. We also observed that the growth rate of GaN : Si films was influenced by the Si doping and the parasitic reactions. The growth rate decreased with the increase of SiH4/TMGa ratio and was larger in larger parasitic reactions reactor. Sidoped GaN films with carrier concentration of 2 10 19 cm @3 , electron mobility of 120 cm 2 /V s, FWHM of the bandedge emission of only 60 meV at room temperature, and no yellow emission were obtained. r 2001 Elsevier Science

Electroluminescence from the sidewall quantum wells in the V-shaped pits of InGaN light emitting diodes

InGaN/GaN multi-quantum well (MQW) light emitting diodes with heavily Mg doped and unintentionally doped (UID) low-temperature Al0.2Ga0.8N electron blocking layer (EBL) were investigated. Broad short-wavelength electroluminescence peak, which has strong relative intensity to the main emission, was found in the UID-EBL sample at cryogenic temperatures. Study suggests that the broad peak is emitted by the sidewall MQWs. This result indicates that the electroluminescence of sidewall MQWs, in which the carrier density is high enough, can be detected at cryogenic temperatures. The lineshape variation with current density reveals detailed information on the process of carrier injection into the sidewall MQWs.

The effect of silicon doping in the barrier on the electroluminescence of InGaN/GaN multiple quantum well light emitting diodes

InGaN/GaN multiple quantum well (MQW) light emitting diodes were grown on silicon substrate by metal organic chemical vapor deposition. A different barrier was heavily doped with silicon based on the same structure. Temperature dependent electroluminescence was performed on the devices. The results reveal that heavily doping the barrier distant from the n-type layer with silicon causes two emission peaks. As the doped barrier gets closer to n-type layer, the energy gap between the two peaks becomes narrower. Silicon doped in the barrier is believed to generate p-n junction built-in field from the doped barrier towards p-type layer. This field compensates the piezoelectric field in the well(s) between the doped barrier and p-type layer. It results in higher emission energy of this (these) well(s). When the doped barrier gets closer to the n-type layer, the compensation is less significant.

MOCVD growth of MgSe thin films on GaAs substrates

MgSe thin films have been grown by metal-organic chemical vapor deposition on GaAs substrates. Our experimental results show that the crystal structure of MgSe depends strongly on both the growth temperature and the substrate orientation. Using the X-ray diffraction technique, we observed the three phases of MgSe; the rock salt, wurtzite and zincblende structures. The lattice constant of zincblende MgSe was determined to be 5.96 A.