Carrier Compensation Mechanism in Wide Bandgap II-VI Semiconductors

为了获得可靠的p型宽禁带II-VI半导体，Park等人和Ohkawa等人已经有了漫长的历史。他们是第一个成功地使用活性氮作为掺杂剂的分子束外延生长的ZnSe，这一重要步骤导致了II-VI蓝绿激光二极管的第一次展示。然而，目前的关键问题仍然是如何获得高电导率的p型材料，并指出空穴补偿的机理。本研究利用高分辨光谱、光致发光激发、选择性光致发光激发、深能级光谱等手段对锌硒：氮的杂质能级进行了鉴定和表征。近几年来，氮气被认为是分子束外延生产p型锌硒的最佳掺杂剂。补偿机制似乎是形成了这种新的施主中心，其束缚能为57 meV。深施主的证据来自于PL、…中DAP线的出现较高氮浓度的ZnSe：N具有更多的光谱。此外，通过详细的光学研究，在高掺杂的ZnSe：N中发现了结合能为88 meV的施主和结合能为170 meV的受主。本文提出了N掺杂锌的能量洛夫尔图，从实验和理论上将补偿现象归因于以下几个原因：(1)本征点缺陷的补偿(如由N-受主和邻近锌位(N&lt；Se&Gt；-Zn-V&lt；Se&Gt；)上的Se空位组成的施主类型的复合缺陷)；(Ii)由N团簇补偿，例如由N受主和相邻锌位上的N原子组成的双施主(N&lt；Se&GT；(3)间隙位N原子的补偿(N&lt；Int&>t；)；(4)强的晶格驰豫。此外，氮可以形成较深的而不是较浅的受体，如(N_&lt；Se&gt；-Zn-N_&lt；Se&gt；)。在光学研究中发现的深施主和受主中心的起源与这些N-相关的复杂缺陷相关，并提出了。较少

There has been a lomg history of attempts to achieve reliable p-type wide bandgap II-VI semiconductors Park et al.and Ohkawa et al.were the first to successfully dope ZnSe grown by MBE using active nitrogen as a dopant and this important step led to the first demonstration of II-VI blue-green laser diodes. IIowever, the key issue remains how to achieve high conductivity p-type materials and pinpoints the mechanism of hole compensation. In this study, the identification and characterization of impurity levels in ZnSe : N have been extensively made by means of high resolution spectroscopy, photoluminescent excitation, selective photoluminescent excitation, deep level spectroscopy.Over the past few years nitrogen has been found to be the best dopant in the production of p-type ZnSe by MBE.The mechanism of compensation appears to be the formation of this new type of donor center with a binding energy of 57meV.Evidence for the deep donor comes from the appearance of the DAP lines in the PL, … More spectra from ZnSe : N with a high N concentration. Additionally, a donor with a binding energy of 88meV and an acceptor with a binding energy of 170meV have been found in highly doped ZnSe : N through detailed optical studie. The energy lovel diagram has been proposed for N-doped ZnSe.The caues of the compensation phenomenon have been attributed experimentally and theoretically to a number of origins : (i) compensation by native point defects (eg.a donor-type complex defect consisting of an N-acceptor and a selenium vacancy on a next nearest neighbor site (N_<Se>-Zn-V_<Se>) ; (ii) compensation by N clusters, for instance, a double donor consisting of a N acceptor and a N atom on adjacent Zn site (N_<Se>-N_<Zn>) ; (iii) compensation by N atoms at interstitial sites (N_<int>) ; and (iv) strong lattice relaxation. In addition, the nitrogen could form deep instead of shallow acceptors such as (N_<Se>-Zn-N_<Se>). The origins of the deep donor and acceptor centers found in the optical studies have been correlated to these N-associated complex defects and proposed. Less