JPH03123086A - Manufacture of infrared detecting element - Google Patents
Manufacture of infrared detecting elementInfo
- Publication number
- JPH03123086A JPH03123086A JP1260080A JP26008089A JPH03123086A JP H03123086 A JPH03123086 A JP H03123086A JP 1260080 A JP1260080 A JP 1260080A JP 26008089 A JP26008089 A JP 26008089A JP H03123086 A JPH03123086 A JP H03123086A
- Authority
- JP
- Japan
- Prior art keywords
- crystal
- hgcdte
- sensing element
- temperature
- resistance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 239000013078 crystal Substances 0.000 claims abstract description 40
- 229910000661 Mercury cadmium telluride Inorganic materials 0.000 claims abstract description 19
- 239000000289 melt material Substances 0.000 claims abstract description 10
- 238000000034 method Methods 0.000 claims abstract description 10
- 239000007791 liquid phase Substances 0.000 claims abstract description 9
- 229910052793 cadmium Inorganic materials 0.000 claims abstract description 8
- 229910052753 mercury Inorganic materials 0.000 claims abstract description 7
- 239000002019 doping agent Substances 0.000 claims abstract description 6
- 239000000758 substrate Substances 0.000 claims description 13
- 238000001816 cooling Methods 0.000 abstract description 6
- 229910052714 tellurium Inorganic materials 0.000 abstract description 4
- 230000007423 decrease Effects 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 9
- 239000003708 ampul Substances 0.000 description 8
- 239000010453 quartz Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000002109 crystal growth method Methods 0.000 description 3
- 229910004613 CdTe Inorganic materials 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 239000003507 refrigerant Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000001931 thermography Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Abstract
Description
【発明の詳細な説明】
概要
赤外線検知素子の製造方法に関し、
素子の動作温度である低温領域で多少温度が変動しても
素子抵抗が変化しない赤外線検知素子の製造方法を提供
することを目的とし、
基板上にＨｇＣｄＴｅ結晶を液相エピタキシャル成長さ
せ、該ＨｇＣｄＴｅ結晶を加工して赤外線検知素子とし
て使用する赤外線検知素子の製造方法において、ＨｇＣ
ｄＴｅのメルト材料中にＨｇ、Ｃｄ又はＴｅの同族元素
を所定量ドーパントとして添加し、ＨｇＣｄ４ｅ結晶の
移動度を赤外線検知素子の動作温度である低温領域で減
少させるように構成する。[Detailed Description of the Invention] Overview Regarding a method for manufacturing an infrared sensing element, an object of the present invention is to provide a method for manufacturing an infrared sensing element in which the element resistance does not change even if the temperature changes slightly in the low temperature region that is the operating temperature of the element. , In a method for manufacturing an infrared sensing element, in which a HgCdTe crystal is grown on a substrate by liquid phase epitaxial growth, and the HgCdTe crystal is processed and used as an infrared sensing element,
A predetermined amount of a homologous element of Hg, Cd, or Te is added as a dopant to the dTe melt material, so that the mobility of the HgCd4e crystal is reduced in the low temperature region that is the operating temperature of the infrared sensing element.
産業上の利用分野 本発明は赤外線検知素子の製造方法に関する。Industrial applications The present invention relates to a method for manufacturing an infrared sensing element.
赤外線センサは目標物体に接触することなく物体の存在
、形状、温度、組成等を知ることができるため、人工衛
星による気象観測、防犯、防災、地質・資源調査、赤外
線サーモグラフィによる医療用等の多くの分野で用いら
れている。このような赤外線センサの内、二元又は三元
化合物半導体を利用した光電効果型センサは、感度が高
く、応答速度も速いが、通常素子の概略液体窒素温度で
の冷却が必要である。Infrared sensors can detect the presence, shape, temperature, composition, etc. of a target object without coming into contact with it, so it is used in many applications such as weather observation using artificial satellites, crime prevention, disaster prevention, geological and resource surveys, and medical use using infrared thermography. It is used in the field of Among such infrared sensors, photoelectric effect sensors using binary or ternary compound semiconductors have high sensitivity and fast response speed, but usually require cooling of the element to approximately the temperature of liquid nitrogen.
光電効果型センサは、光導電型、光起電力型、ＭＩＳ型
に大別されるが、この内光導電型センサを構成する素子
としてＨｇＣｄＴｅ結晶がよ（用いられる。ＨｇＣｄＴ
ｅ結晶は通常液相エピタキシャル結晶成長方法により製
造され、この結晶を加工して赤外線検知素子として使用
している。この赤外線検知素子は、光照射時の抵抗変化
を利用したものであり、半導体素子であるためにその抵
抗は温度とともに変化する。Photoelectric effect sensors are broadly classified into photoconductive type, photovoltaic type, and MIS type, and among these, HgCdTe crystal is often used as the element constituting the photoconductive type sensor.
E-crystals are usually manufactured by a liquid phase epitaxial crystal growth method, and this crystal is processed and used as an infrared sensing element. This infrared sensing element utilizes a change in resistance upon irradiation with light, and since it is a semiconductor element, its resistance changes with temperature.
従来の技術
易蒸発性の成分元素を含む化合物半導体結晶に適した一
般的な方法として、密封回転式の液相エピタキシャル結
晶成長法を第４図及び第５図により説明する。第４図を
参照すると、基板保持治具１は、円筒状の石英アンプル
２内に内接する外径と所定長さの、例えば石英ガラスあ
るいはカーボン材からなる円柱の外周部中央の一部を切
り欠いた切欠凹部３を有している。この切欠凹部３内の
対向壁面には、結晶成長用の基板４を横架する形に水平
保持するための溝５，５が形成されている。BACKGROUND OF THE INVENTION As a general method suitable for compound semiconductor crystals containing easily evaporated component elements, a sealed rotation liquid phase epitaxial crystal growth method will be explained with reference to FIGS. 4 and 5. Referring to FIG. 4, the substrate holding jig 1 cuts a part of the center of the outer circumference of a cylinder made of quartz glass or carbon material, which has an outer diameter and a predetermined length and is inscribed in a cylindrical quartz ampoule 2. It has a cutout recess 3. Grooves 5, 5 for horizontally holding the crystal growth substrate 4 in a horizontally suspended manner are formed on opposing wall surfaces within the cutout recess 3.
そして、液相エピタキシャル結晶成長に際しては、治具
１の切欠凹部３内に例えばＣｄＴｅからなる結晶成長用
基板４が収容された基板ホルダ６を水平に掛は渡した形
に保持し、基板４及び基板ホルダ６と、予め所定組成比
に秤量されたＨｇＣｄ 、、Ｔ ｅからなる結晶成長用
のメルト材料７とを図示のように石英アンプル２内に配
設し、内部を排気した後、基板保持治具１が内部で動か
ないように気密に封止する。During liquid phase epitaxial crystal growth, the substrate holder 6 containing the crystal growth substrate 4 made of, for example, CdTe is held in the cutout recess 3 of the jig 1 in a horizontally hanging manner. A substrate holder 6 and a melt material 7 for crystal growth made of HgCd, Te, weighed in advance to a predetermined composition ratio are arranged in a quartz ampoule 2 as shown in the figure, and after the inside is evacuated, the substrate is held. The jig 1 is hermetically sealed so that it does not move inside.
しかる後、石英アンプル２を図示しないエビクキシャル
結晶成長炉内に配置し、結晶成長温度よりも高い所定温
度に加熱して、第５図（Ａ）に示すように、石英アンプ
ル２内の結晶成長用のメルト材料７を溶融させる。そし
て、石英アンプル２を１８０°回転して基板４面を溶融
した結晶成長用メルト材料７に接触させ、炉内温度を所
定の結晶成長温度に低下させると、同図（Ｂ）に示すよ
うに、基板４上にＨｇ＋−ＣｄつＴｅからなる結晶層８
が成長する。次に、所定の厚さの結晶層が形成された時
点で、同図（Ｃ）に示すように、石英アンプル２を再び
１８０°反転させることにより、基板４をメルト材料７
内から除去して結晶成長を停止させ、その後、炉内より
石英アンプル２を除冷しながら引き出し、石英アンプル
２を開封し、結晶層８が形成された基板４を基板保持治
具１から取り出すようにしている。Thereafter, the quartz ampoule 2 is placed in an evixaxial crystal growth furnace (not shown), and heated to a predetermined temperature higher than the crystal growth temperature, as shown in FIG. 5(A). The melt material 7 is melted. Then, when the quartz ampoule 2 is rotated 180 degrees to bring the 4 surfaces of the substrate into contact with the melt material 7 for crystal growth, and the temperature inside the furnace is lowered to a predetermined crystal growth temperature, as shown in FIG. , a crystal layer 8 made of Hg+-Cd and Te on the substrate 4.
grows. Next, when a crystal layer of a predetermined thickness is formed, as shown in FIG.
The quartz ampoule 2 is removed from the inside to stop crystal growth, and then the quartz ampoule 2 is pulled out from inside the furnace while being slowly cooled, the quartz ampoule 2 is unsealed, and the substrate 4 on which the crystal layer 8 is formed is taken out from the substrate holding jig 1. That's what I do.
このような液相エピタキシャル結晶成長方法によりＨｇ
ＣｄＴｅ結晶を成長させた後、この結晶に適当な加工を
加えて赤外線検知素子を製造している。By such a liquid phase epitaxial crystal growth method, Hg
After growing a CdTe crystal, this crystal is subjected to appropriate processing to manufacture an infrared sensing element.
発明が解決しようとする課題
光導電型赤外線検知素子は、光が照射されたことによっ
て発生した過剰キャリアによって検知素子の抵抗が小さ
くなることを利用した素子である。Problems to be Solved by the Invention A photoconductive infrared sensing element is an element that utilizes the fact that the resistance of the sensing element decreases due to excess carriers generated by irradiation with light.
即ち、検知素子の抵抗をＲ１キャリア濃度をｎ１移動度
をμとすると、Ｒ＝１／（ｎ・μ）で表される。しかし
、この素子は半導体素子であるために、その抵抗は温度
とともに変化する。これは、キャリア濃度及び移動度が
温度とともに変化する半導体に固有の現象である。That is, when the resistance of the sensing element is R1, the carrier concentration is n1, and the mobility is μ, it is expressed as R=1/(n·μ). However, since this element is a semiconductor element, its resistance changes with temperature. This is a phenomenon unique to semiconductors in which carrier concentration and mobility change with temperature.
高性能の赤外線検知素子を作成するためには、検知素子
を１０００／λ。（λ。はカットオフ波長）以下まで冷
却する必要がある。したがって、８〜１４μｍ帯用赤外
線横用赤外線検知素子に付近までの冷却を必要とする。In order to create a high-performance infrared sensing element, the sensing element must be 1000/λ. (λ is the cutoff wavelength) or below. Therefore, it is necessary to cool the infrared ray detection element for horizontal infrared rays in the 8 to 14 μm band to a temperature close to that level.
このような低温への冷却は、例えば液体窒素のような冷
媒により冷却するか、或いはジュールトムソン式の低温
冷却器等により冷却している。しかし、従来採用されて
いる冷却方法によると、冷却温度の変動を無視すること
はできない。Cooling to such a low temperature is carried out, for example, by using a refrigerant such as liquid nitrogen, or by using a Joule-Thomson type low temperature cooler. However, according to conventionally employed cooling methods, fluctuations in cooling temperature cannot be ignored.
第６図は従来のＨｇＣｄＴｅ結晶のキャリア濃度特性図
であり、第７図は移動度特性図である。FIG. 6 is a carrier concentration characteristic diagram of a conventional HgCdTe crystal, and FIG. 7 is a mobility characteristic diagram.
上述したように素子抵抗Ｒは素子のキャリア濃度の逆数
及び移動度の逆数に比例するから、即ち、Ｒ＝１／（ｎ
・μ）であるから、従来の赤外線検−
−
知素子の抵抗特性図は第６図のグラフの逆数及び第７図
のグラフの逆数を合成して第８図に示したようなものと
なる。即ち、赤外線検知素子の動作温度である８０〜９
０にでは、温度に従って素子抵抗Ｒが変化する。As mentioned above, the element resistance R is proportional to the reciprocal of the carrier concentration and the reciprocal of the mobility of the element, that is, R=1/(n
・μ) Therefore, the resistance characteristic diagram of the conventional infrared detection element is as shown in Figure 8 by combining the reciprocal of the graph in Figure 6 and the reciprocal of the graph in Figure 7. . That is, the operating temperature of the infrared sensing element is 80-9.
At 0, the element resistance R changes according to temperature.
ところで、この赤外線検知素子は一定のバイアス電流で
動作しているために、温度変動により素子抵抗が変化す
ると、素子の端子間の電圧が変化してしまう。この電圧
変化分は、実際に検知素子に光が当たって生じる信号電
圧とは異なりノイズである。このように第８図に示すよ
うな特性を持つＨｇＣｄＴｅ結晶を用いて赤外線検知素
子を作成すると、温度変動に起因する信号ノイズが発生
するという問題があった。By the way, since this infrared sensing element operates with a constant bias current, if the element resistance changes due to temperature fluctuation, the voltage between the terminals of the element will change. This voltage change is noise, unlike the signal voltage that occurs when light actually hits the sensing element. When an infrared sensing element is fabricated using a HgCdTe crystal having the characteristics shown in FIG. 8, there is a problem in that signal noise is generated due to temperature fluctuations.
本発明はこのような点に鑑みてなされたものであり、そ
の目的とするところは、素子の動作温度である低温領域
で多少温度が変動しても素子抵抗が変化しない、赤外線
検知素子の製造方法を提供することである。The present invention has been made in view of these points, and its purpose is to manufacture an infrared sensing element in which the element resistance does not change even if the temperature fluctuates slightly in the low-temperature region that is the operating temperature of the element. The purpose is to provide a method.
課題を解決するための手段
上述した目的を達成するために、基板上にＨｇＣｄＴｅ
結晶を液相エピタキシャル成長させ、該ＨｇＣｄＴｅ結
晶を加工して赤外線検知素子として使用する赤外線検知
素子の製造方法において、ＨｇＣｄＴｅのメルト材料中
にＨｇ、Ｃｄ又はＴｅの同族元素（中性不純物）を所定
量ドーパントとして添加。実際にＨｇＣｄＴｅのメルト
材料中に添加する中性不純物としては、Ｈｇ、Ｃｄの同
族元素であるＺｎ及びＴｅの同族元素であるＳｅ。Means for Solving the Problems In order to achieve the above-mentioned objectives, HgCdTe was deposited on the substrate.
In a method for manufacturing an infrared sensing element in which a crystal is grown by liquid phase epitaxial growth and the HgCdTe crystal is processed to be used as an infrared sensing element, a predetermined amount of a homologous element (neutral impurity) of Hg, Cd or Te is added to a melt material of HgCdTe. Added as a dopant. Neutral impurities actually added to the HgCdTe melt material include Hg, Zn, which is a homologous element of Cd, and Se, which is a homologous element of Te.
Ｓ等があげられる。Examples include S.
添加量としてはＨｇＣｄＴｅ結晶の移動度を赤外線検知
素子の動作温度である低温領域で十分に減少させる量で
あることが必要である。The amount added must be such that the mobility of the HgCdTe crystal is sufficiently reduced in the low temperature region that is the operating temperature of the infrared sensing element.
作 用
このようにして形成された結晶のキャリア濃度特性図は
第２図に示すとおりであり、第６図に示した従来の特性
図と変わらないが、移動度は第３図に示すより１２０に
以下の低温側において減少する。第２図及び第３図に示
すような特性を有するＨｇＣｄＴｅ結晶から赤外線検知
素子を作成すると、検知素子の抵抗ＲはＲ＝１／（ｎ・
μ）であるから、第１図のグラフに示すようになり、素
子の動作温度である低温領域（７７に〜１００Ｋ）で素
子抵抗が一定となる。検知素子がこのような抵抗特性を
有していると、例え検知素子の冷却温度が変動しても素
子抵抗は変化することがなく、ノイズが発生することは
ない。Effect The carrier concentration characteristic diagram of the crystal thus formed is as shown in Figure 2, which is the same as the conventional characteristic diagram shown in Figure 6, but the mobility is 120% higher than that shown in Figure 3. decreases on the low temperature side below. When an infrared sensing element is made from a HgCdTe crystal having the characteristics shown in FIGS. 2 and 3, the resistance R of the sensing element is R=1/(n・
μ), as shown in the graph of FIG. 1, the element resistance becomes constant in the low temperature range (77 to 100 K), which is the operating temperature of the element. If the sensing element has such a resistance characteristic, even if the cooling temperature of the sensing element changes, the element resistance will not change and no noise will occur.
発明の効果
本発明は以上を詳述したように、素子の動作温度である
低温領域で温度変動が生じても、素子抵抗が変化しない
赤外線検知素子を製造できるため、冷却温度の変動によ
りノイズの生じない赤外線検知素子を実現できるという
効果を奏する。Effects of the Invention As described in detail above, the present invention can manufacture an infrared sensing element in which the element resistance does not change even if temperature fluctuations occur in the low-temperature region that is the operating temperature of the element. This has the effect of realizing an infrared detecting element that does not generate light.
第２図は本発明結晶のキャリア濃度特性図、第３図は本
発明結晶の移動度特性図、
第４図は従来の密封回転式の液相エピタキシャル結晶成
長装置の一部破断斜視図、
第５図は同装置を使用した結晶成長工程図、第６図は従
来技術による結晶のキャリア濃度特性図、
第７図は同移動度特性図、
第８図は従来の赤外線検知素子の抵抗特性図である。FIG. 2 is a carrier concentration characteristic diagram of the crystal of the present invention, FIG. 3 is a mobility characteristic diagram of the crystal of the present invention, FIG. 4 is a partially cutaway perspective view of a conventional sealed rotary liquid phase epitaxial crystal growth apparatus, Figure 5 is a diagram of the crystal growth process using the same device, Figure 6 is a carrier concentration characteristic diagram of a crystal according to the conventional technology, Figure 7 is a mobility characteristic diagram of the same, and Figure 8 is a resistance characteristic diagram of a conventional infrared sensing element. It is.
１・・・基板保持治具 ２・・・石英アンプル ４・・・基板 ７・・・メルト材料 ８・・・結晶層。1... Board holding jig 2...Quartz ampoule 4... Board 7...Melt material 8...Crystal layer.
第１図は本発明による赤外線検知素子の抵抗特性図、 FIG. 1 is a resistance characteristic diagram of an infrared sensing element according to the present invention.
Claims (1)
成長させ、該ＨｇＣｄＴｅ結晶を加工して赤外線検知素
子として使用する赤外線検知素子の製造方法において、 ＨｇＣｄＴｅのメルト材料（７）中にＨｇ、Ｃｄ又はＴ
ｅの同族元素を所定量ドーパントとして添加し、 ＨｇＣｄＴｅ結晶の移動度を赤外線検知素子の動作温度
である低温領域で減少させることを特徴とする赤外線検
知素子の製造方法。[Claims] In a method for manufacturing an infrared sensing element, in which an HgCdTe crystal is grown on a substrate (4) by liquid phase epitaxial growth, and the HgCdTe crystal is processed to be used as an infrared sensing element, the HgCdTe melt material (7) contains: Hg, Cd or T
A method for producing an infrared sensing element, characterized in that a predetermined amount of a homologous element of e is added as a dopant to reduce the mobility of the HgCdTe crystal in a low temperature region that is the operating temperature of the infrared sensing element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1260080A JPH03123086A (en) | 1989-10-06 | 1989-10-06 | Manufacture of infrared detecting element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1260080A JPH03123086A (en) | 1989-10-06 | 1989-10-06 | Manufacture of infrared detecting element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03123086A true JPH03123086A (en) | 1991-05-24 |
Family
ID=17343025
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1260080A Pending JPH03123086A (en) | 1989-10-06 | 1989-10-06 | Manufacture of infrared detecting element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03123086A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5964063A (en) * | 1996-07-22 | 1999-10-12 | Honda Giken Kogyo Kabushiki Kaisha | Motor-vehicle door having window winder, method of assembling the door, and window sash assembly suitable for use in the door |
-
1989
- 1989-10-06 JP JP1260080A patent/JPH03123086A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5964063A (en) * | 1996-07-22 | 1999-10-12 | Honda Giken Kogyo Kabushiki Kaisha | Motor-vehicle door having window winder, method of assembling the door, and window sash assembly suitable for use in the door |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Tufte et al. | Growth and Properties of Hg1− x Cd x Te Epitaxial Layers | |
| Gildart et al. | Some semiconducting properties of bismuth trisulfide | |
| US3725135A (en) | PROCESS FOR PREPARING EPITAXIAL LAYERS OF Hg{11 {118 {11 Cd{11 Te | |
| US2953529A (en) | Semiconductive radiation-sensitive device | |
| JPS6021960B2 (en) | Manufacturing method of Hg↓1-↓xCd↓xTe composition layer | |
| US4086555A (en) | Photoconductive sensor | |
| US3224911A (en) | Use of hydrogen halide as carrier gas in forming iii-v compound from a crude iii-v compound | |
| US2844737A (en) | Semi-conductive materials | |
| US4642142A (en) | Process for making mercury cadmium telluride | |
| US3105906A (en) | Germanium silicon alloy semiconductor detector for infrared radiation | |
| US4081819A (en) | Mercury cadmium telluride device | |
| JPH03123086A (en) | Manufacture of infrared detecting element | |
| US3963540A (en) | Heat treatment of mercury cadmium telluride | |
| US3033791A (en) | Method of manufacturing high-ohmic cadmium telluride for use in semiconductor devices or photo-sensitive devices | |
| US3574140A (en) | Epitaxial lead-containing photoconductive materials | |
| Hobgood et al. | Growth and characterization of Indium-doped silicon for extrinsic IR detectors | |
| JP6713341B2 (en) | Compound semiconductor substrate and manufacturing method thereof | |
| US8969803B2 (en) | Room temperature aluminum antimonide radiation detector and methods thereof | |
| US4487813A (en) | Composition control of CSVPE HgCdTe | |
| US5028296A (en) | Annealing method | |
| US3945935A (en) | Semiconductive metal chalcogenides of the type Cu3 VS4 and methods for preparing them | |
| Stelzer et al. | Mercury cadmium telluride as an infrared detector material | |
| JPH06340499A (en) | Formation of cadmium mercury telluride crystal and production of infrared detector | |
| JP2915935B2 (en) | Semiconductor thin film material | |
| Alexiev et al. | Gamma-ray detectors from thermally annealed Bridgman-grown CdTe |