新一代长波长红外探测器

文章旨在介绍适应于长波红外焦平面阵列技术发展的红外探测器，由于篇幅的关系，本文着重评述ＩｎＡｓＳｂ应变层超晶格红外探测器和ＧａＡｓ／ＧａＡｌＡｓ多量子阱红外探测器的特点、器件结构、主要制作工艺，性能参数，以及急需要解决的一些问题。     

The growth of InAsSb/InAsP strained-layer superlattices for use in infrared emitters

We describe the metalorganic chemical vapor deposition of InAsSb/InAsP strained-layer superlattice (SLS) active regions for use in mid-infrared emitters. These SLSs were grown at 500°C, and 200 Torr in a horizontal quartz reactor using TMIn, TESb, AsH₃, and PH₃. By changing the layer thickness and composition, we have prepared structures with low temperature (≤20K) photoluminescence wavelengths ranging from 3.2 to 4.4 μm. Excellent performance was observed for a SLS light emitting diode (LED) and both optically pumped and electrically injected SLS lasers. An optically pumped, double heterostructure laser emitted at 3.86 μm with a maximum operating temperature of 240K and a characteristic temperature of 33K. We have also made electrically injected lasers and LEDs utilizing a GaAsSb/InAs semi-metal injection scheme. The semi-metal injected, broadband LED emitted at 4 μm with 80 μW of power at 300K and 200 mA average current. The InAsSb/InAsP SLS injection laser emitted at 3.6 μm at 120K.     

基于GaAs衬底的晶格失配InAs0.07Sb0.93薄膜的红外探测特性

利用MBE的方法在晶格失配的GaAs衬底上制备了新型红外探测材料InAs0.07Sb0.93薄膜。并利用电子束刻蚀的方法在InAs0.07Sb0.93薄膜表面进行了电极的制备。使用标准黑体及傅里叶红外光谱仪对制备成的光电导器件的黑体响应、暗电流以及光电流谱进行了测试,结果表明,所制备的红外探测器获得了响应峰值为4μm、响应半峰宽为4μm的中波宽带响应。     

Theoretical modelling of XBn T2SLs InAs/InAsSb/B-AlAsSb mid-wave detector operating below thermoelectrical cooling

The paper reports on the barrier mid-wave infrared InAs/InAsSb (x_Sb = 0.4) type-II superlattice detector operating below thermoelectrical cooling. AlAsSb with Sb composition, x_Sb = 0.97; barrier doping, N_D < 2×10¹⁶ cm^?3 leading to valence band offset below 100 meV in relation to the active layer doping, N_D = 5×10¹⁵ cm^?3 was proved to be proper material not introducing extra barrier in valence band in the analyzed temperature range in XBn architectures. The detectivity of the simulated structure was assessed at the level of ～ 10¹¹ Jones at T ～ 100 K assuming absorber thickness, d = 3 μm. The detector’s architecture for high frequency response operation, τ_s = 420 ps (T ～ 77 K) was presented with a reduced active layer of d = 1 μm.     

Type-II superlattice detectors for free space optics applications and higher operating temperature conditions

The utmost limit performance of interband cascade detectors optimized for the longwave range of infrared radiation is investigated in this work. Currently, materials from the III–V group are characterized by short carrier lifetimes limited by Shockley-Read-Hall generation and recombination processes. The maximum carrier lifetime values reported at 77 K for the type-II superlattices InAs/GaSb and InAs/InAsSb in a longwave range correspond to ～200 and ～400 ns. We estimated theoretical detectivity of interband cascade detectors assuming above carrier lifetimes and a value of ～1–50 μs reported for a well-known HgCdTe material. It has been shown that for room temperature the limit value of detctivity is of ～3–4×10¹⁰ cmHz^1/2/W for the optimized detector operating at the wavelength range ～10 μm could be reached.     

InAs0.96Sb0.04红外薄膜的光学性质研究

采用水平滑移石墨舟液相外延生长技术在n型(100)InAs衬底上生长了InAs0.96Sb0.04薄膜.在1.5~5.5 eV光子能量范围采用紫外—可见光椭圆偏振光谱仪于室温下测试了其介电函数谱ε(E).基于电子带间跃迁和联合态密度理论,采用S.Adachi的MDF模型对ε(E)进行了拟合,并计算了各种临界点电子跃迁对ε(E)的贡献.结果表明:实验数据与模型吻合得非常好,E1和E1 Δ1跃迁发生在布里渊区(BZ)的Λ轴或L点,分别对应于M1型临界点Λ5v→Λ6c(或L4v.5→L6c)和Λ6v→Λc6(或L6v→L6c)跃迁;E2跃迁是由于M1型和M2型鞍点能量简并引起的,沿着BZ的Σ和Δ轴方向.     

nBn型InAsSb探测器的材料及器件研究

nBn型红外探测器可有效抑制产生-复合电流,进而提高探测器的工作温度。由于制备工艺可移植于III/V族成熟工艺以及存在晶格完全匹配的衬底等优势,InAsSb/AlAsSb材料是nBn型红外探测器的首选。简单介绍了InAsSb/AlAsSb nBn型红外探测器的研究现状、工作原理以及近期的研究成果。通过生长试验实现了良好的材料表面质量、晶体质量和光学性能。相关结果表明,在制备器件时,nBn结构中势垒层的掺杂浓度不应低于8×1016cm-3,否则就不利于减小nBn型器件的暗电流。     

nBn InAsSb/AlAsSb中波红外探测器的设计

对nBn势垒型InAsSb/AlAsSb中波红外探测器材料进行了系统深入的理论研究.通过理论计算势垒层的厚度、组分和掺杂等结构参数对器件能带结构、暗电流和光电流的影响,分析了势垒性的温度特性、器件输运特性,揭示了nBn势垒型中波红外探测器高温工作的机制,探索降低器件暗电流的方法.完成nBn势垒型锑化物材料系统的优化设计,为高温工作的锑化物中波红外探测器研制提供理论基础和支持.     

非致冷InAsSb中长波红外探测器研究评述

作为一种新兴的红外光电材料,InAsSb由于其禁带宽度窄、电子迁移率极高等优良特性受到了世界各国的广泛关注。InAsSb探测器的优势在于：对中长波红外波段的探测而言,其在室温下也具有很高的探测率,同时InAsSb探测器具有比HgCdTe探测器更高的响应速度。这些优势使得InAsSb探测器可制成非致冷型红外探测器,容易实现仪器的小型化,大大降低成本,在某些场合成为能够取代HgCdTe的理想材料。文章分别对InAsSb探测器国内和国外的研究近况作一简要评述,从而显示出在中长波红外波段InAsSb材料广阔的应用前景。     

A method to extend wavelength into middle-wavelength infrared based on InAsSb/(Al)GaSb interband transition quantum well infrared photodetector

We present a method to extend the operating wavelength of the interband transition quantum well photodetector from an extended short-wavelength infrared region to a middle-wavelength infrared region. In the modified In As Sb quantum well, Ga Sb is replaced with Al Sb/Al Ga Sb, the valence band of the barrier material is lowered, the first restricted energy level is higher than the valence band of the barrier material, the energy band structure forms type-II structure. The photocurrent spectrum manifest that the fabricated photodetector exhibits a response range from 1.9 μm to 3.2 μm with two peaks at 2.18 μm and 3.03 μm at 78 K.