【摘要】 通过优化Mg流量增强了MOCVD生长的GaN薄膜的p型电导并改善了晶体质量.Hall测量结果表明空穴浓度首先随着Mg流量的升高而升高,达到极大值后开始降低;迁移率始终随Mg流量的升高而降低.最优的样品在室温下空穴浓度达到4.1×1017cm-3,电阻率降至1Ω.cm.考虑施主型缺陷MGaVN的自补偿作用,计算了空穴浓度随掺杂浓度变化的曲线关系.计算结果表明自补偿系数随掺杂浓度的增大而增大;空穴浓度首先随掺杂浓度的增大而增加,在受主浓度为NA≈4×1019左右时达到极大值,之后随着掺杂浓度的增大而迅速降低.XRD数据表明在实验范围内晶体缺陷密度随着掺杂浓度的降低而降低.更多还原

【Abstract】 p-type conductivity and crystal quality of Mg-doped GaN grown by MOCVD have been improved through optimization of the magnesium flow rate.The hole concentration first increased and then decreased with the magnesium flow rate while the mobility decreased monotonously.The optimum sample reached a hole concentration of 4.1×1017cm-3 and a resistivity of 1Ω·cm.Based on a self-compensation model involving the deep donor MGaVN,we calculate the hole concentration as a function of magnesium doping concentration NA,which indicates that the self-compensation coefficient increases with NA;the hole concentration first increases with NA and reaches a maximum at NA≈4×1019,then decreases rapidly as doping concentration increases.XRD also indicate that dislocation density decreased as magnesium flow rate decreased.更多还原