文章信息/Info

Title:

Research Progress on Characterization and Application of Relaxation Semiconductors

作者:

余競一; 介萬奇

西北工業(yè)大學材料學院 輻射探測材料與器件工信部重點實驗室

Author(s):

YU Jingyi; JIE Wanqi

Key Laboratory of Radiation Detection Materials and Devices, Ministry of Industry and Information Technology,
School of Materials Science and Engineering, Northwestern Polytechnical University

關(guān)鍵詞:

弛豫半導體; 壽命半導體; 介電弛豫; 少子注入; 多子耗盡效應; 光生載流子分離; 雙極性輸運; 電流-電壓測試; 輻射探測器

Keywords:

relaxation semiconductor;  lifetime semiconductor;  dielectric relaxation;  minority carrier injection;  majority carrier depletion;  photocarrier separation;  ambipolar transport;  current�瞯oltage test;  radiation detector

DOI:

10.7502/j.issn.1674-3962.2018.11.02

文獻標志碼:

A

摘要:

介電弛豫時間大于載流子壽命的半導體為弛豫半導體，反之為壽命半導體。因為介電弛豫時間正比于電阻率，所以弛豫半導體一般為高阻半導體，例如補償半導體、非晶半導體或低溫下的半導體。在弛豫半導體中，由于材料恢復電中性的過程慢于載流子濃度恢復質(zhì)量作用定律的過程，所以必須考慮空間電荷，包括自由電荷和陷阱所帶電荷，對載流子輸運的影響。少子注入會導致弛豫半導體多子耗盡、壽命半導體多子增加；中性注入會導致弛豫半導體電子空穴分離、壽命半導體發(fā)生雙極性輸運。弛豫半導體的多子耗盡現(xiàn)象可用電流�搽妷簻y試和交流響應測試進行表征，發(fā)現(xiàn)其電流�搽妷禾匦杂傻碗妷合碌臄U展線性區(qū)和高電壓下的超線性區(qū)構(gòu)成，且受陷阱濃度影響。使用載流子動力學測試可直接觀察到弛豫半導體中光注入電子和空穴的分離現(xiàn)象。弛豫半導體獨特的電學性質(zhì)在輻射探測器、抗輻照器件、光電導開關(guān)、溫度傳感器等領(lǐng)域有廣闊的應用價值。

Abstract:

The relaxation semiconductor is a material whose dielectric relaxation time is larger than its carrier lifetime, which is contrary to the lifetime semiconductor. The dielectric relaxation time is proportional to the resistivity, therefore relaxation semiconductors are typically high�瞨esistivity materials such as compensated semiconductors, amorphous semiconductors and semiconductors at low temperatures. In the relaxation semiconductor, due to the process to recover charge neutrality is slower than the recovery of the mass action law, space charges including free and trapped ones determine carrier transport behaviors. In the relaxation semiconductor, minority carrier injection leads to majority carrier depletion and neutral injection leads to separation of injected electrons and holes, while in the lifetime semiconductor lead to majority carrier accumulation and ambipolar transport, respectively. The majority carrier depletion can be characterized by the current�瞯oltage test and the frequency response test. The current�瞯oltage curve of the relaxation semiconductor contains an extended linear regime at low voltages and a superlinear regime at higher voltages. In addition, the curve is affected by trap concentration. The separation of photocarriers can be directly observed by carrier dynamics tests. Unique properties of the relaxation semiconductor have great application prospects in radiation detectors, radiation�瞙ardness devices, photoconductive switches, thermal sensors, etc.