分子束外延高Mg掺杂GaN的发光特性

采用分子束外延技术在蓝宝石衬底上制备Ｍｇ掺杂的立方相ｐ－ＧａＮ，并对其不同温度下的光致发光光谱进行了研究．实验观察到高Ｍｇ掺杂ＧａＮ中施主受主对发光的反常温度行为．理论分析表明，高Ｍｇ掺杂ＧａＮ中施主受主对的发光受到陷阱与受主间竞争俘获非平衡空穴过程和空穴隧穿输运过程的影响．

OPTICAL PROPERTY OF HEAVILY Mg DOPED GaN GROWN BY MBE

Mg doped GaN with cubic structure have been grown by molecular beam epitaxy on sapphire substrate. Temperature dependent photoluminescence of heavily Mg doped GaN have been investigated in order to study the properities of donor acceptor pair recombination. We have found unusual temperature dependent behaviors of donor acceptor pair recombination in heavily Mg doped GaN. The photoluminescence intensity of donor acceptor pair recombination decreases below 35K and then increases as the temperature increases up to 100K. This behavior may be explained by employing three energy level system, e.g. shallow donor level, shallow acceptor level and hole trap level. The main transition processes and their dynamic processes of non equilibrum holes, which bumped by excited laser, have been studied. The holes are caught in the hole traps and they subsequently transfer from the traps to shallow acceptors by tunneling, where recombination with electrons takes place. The theoretical calculations are in accordance with the experiment results. The PL intensity of donor acceptor recombination in heavily Mg doped GaN is determined by the effects of hole trap and tunneling.