back to article Boffins develop nanoscale vacuum tube running at .46 THz

Researchers from NASA and Korea’s National Nanofab Center have cooked up nanoscale vacuum tubes, potentially bringing some of the earliest electronic devices back into the mainstream of technology. As detailed in a new paper from Applied Physics Letters, the tiny tubes were manufactured using the same processes applied to …


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  1. Allan George Dyer
    Thumb Up

    Boffins are busy today...

    How long before a nano vacuum tube device can read data stored on biological non-volatile storage?

  2. jake Silver badge

    Shades of A.E. van Vogt's "Null-A" universe :-)

    If you kiddies haven't read 'em yet, look it up ... Good early SciFi ... not great works of literature, by any stretch, but worth a read if you're into the history of the genra.

    (Yes, I know, Van was a $cientologist for a while. He renounced the scam before Alzheimer's ruined his brain.)

    1. Francis Boyle Silver badge

      Not just van Vogt

      That murmuring you can hear is a thousand golden age SF writers whispering "I told you so" from beyond the grave".

      1. jake Silver badge

        @Francis Boyle (was: Re: Not just van Vogt)

        I have a couple of "law book" glass fronted book cases containing my mother's first edition hard-bound and magazine collection from the golden age ... Sometimes, late at night, I hear the old guard snickering at me, from the North West corner of the office that never sees daylight ;-)

  3. Wile E. Veteran

    Nothing to see here, move along.

    This page is from several years ago.

  4. Charles Osborne

    Google "Mean Free Path" if you't know

    ... what the value is at STP; Chances are very good that the electrons will bump into something.

  5. easyk

    relays have gone nano too

    yep yep

  6. Robert E A Harvey
    Thumb Down


    we measure power in volts now?

    1. Loyal Commenter

      Re: oh?

      You could measure it in electronvolts per year? Works out at about 5 x 10^-27 watts*...

      * note to mods - how about allowing us the use of the <sup> and <sub> tags?

  7. Denarius

    somewhat older in fact

    printed valves were mentioned in an article I read 40 years ago in some US electronics magazine.

    Certainly not as small, but similar concept and ran on relatively low voltages. Went no-where as I never saw another reference until now. Might be just the electronics for Jupiter Moons probes where everything glows in Jupiters radiation belts.

    1. Robert E A Harvey

      Re: somewhat older in fact

      In the late 60s ITT built a marine HF transmitter with 'solid state valves' or 'vacuumless tubes' depending which side of the pond you were from. I never did find out what was inside. They still had heaters & similar anode voltages. The package was ceramic wit a BFO heatsink on the top.

      1. This post has been deleted by its author

      2. Graham Wilson

        @Robert E A Harvey -- Re: somewhat older in fact -- A ceramic power tube methinks.

        If they had heater and anode voltages applied then they were still valves.

        What you have described is a ceramic power tube, usually a triode or tetrode similar to this common 4CX1000A:

        These devices run very hot so ceramic is used instead of glass and it's also a better heat conductor. The heatsink is finned on the inside through which air is forced. They're most commonly used in HF and VHF transmitters, FM, TV etc., and range in power from about 400W to 30,000W or more.

        You'll note in the link the data sheet's earliest date is 1963 which puts it into the time frame to which you refer.

        1. Robert E A Harvey

          Re: @Robert E A Harvey -- somewhat older in fact -- A ceramic power tube methinks.

          Interesting. Yet ITT specifically splashed them as 'vacuumless'. I wonder what was going on?

  8. Tom 7 Silver badge

    Could be disruptive

    should be interesting to see how the 'valve sound' lasts when it cost 2p, switches on instantly and lasts forever.

    Now if someone can do the same at 5kv then my electrostatic wall speakers can be used in summer...

    1. Stoneshop

      Re: Could be disruptive

      "should be interesting to see how the 'valve sound' lasts when it cost 2p, switches on instantly and lasts forever."

      Nah, the Real Valve Sound Connoisseurs will still stick to amps that contribute significantly to global warming, have slightly lethal voltages present at the anode cap, present a serious hernia risk due to the weight of the chassis, transformers and chokes, and require hunting for exotic NOS firebottles every few hundred hours. Otherwise it's not the Real Valve Sound.

      "Now if someone can do the same at 5kv then my electrostatic wall speakers can be used in summer..."

      Just put your amp in the fridge; if you don't want to lose sight of that dull orange glow the obvious choice is to get yourself one of those glass-door units used in bars and such.

      1. Anonymous Coward
        Anonymous Coward

        Re: Could be disruptive

        Still - raises the possibility of a valve-powered iPod. Personally though, I'm holding out for a Walkman that runs off punched paper tape

  9. Graham Wilson
    Thumb Up

    Valves back in the race eh?

    This is not the first time I've seen reports like this about miniaturised vacuum tubes although not on a nano scale.

    Earlier attempts did away with thermionic emission (Richardson equation) which meant that electrons are torn from the cathode by sheer potential difference between cathode and anode.

    Presumably, the requirement for 10 volts here indicates the same principle for cathode emission. 460 GHz is not a bad effort, and presumably these devices would be immune to EMP too -- unless the substrate silicon is swamped.

  10. SoupDragon


    Don't suppose he'd be interested - mine gets clogged up with dog hair too quickly as it is

    1. Big O

      Re: Dyson

      <-- I believe this is yours!

  11. Anonymous Coward

    See you later Space Cowboy ...

    'In space no-one can hear you play your Les Paul through a sweet nano-valve amp'

    1. Stratman

      Re: See you later Space Cowboy ...

      As if..........

      1. Anonymous Coward
        Anonymous Coward

        Re: See you later Space Cowboy ...

        But humbuckers will mitigate the 800000000 Hz hum of cosmic rays that Leo's finest single coil pickups would let through into the uber-amp's circuit! ... Plus activation of a tremolo unit in zero-g might have bizarre inertial effects!!! Play safe Sir and take a Lester. ;-)

        (Just kidding ... I own a Strat and a Telecaster so I'm not immune to their considerable charms.)

        1. This post has been deleted by its author

          1. This post has been deleted by its author

        2. jake Silver badge

          Re: See you later Space Cowboy ...

          I learned to play on a 1961 Les Paul ... Taught my wife and daughter on the same guitar. Today, I mostly play bass (Precision Big Block), but when I feel nostalgic I twiddle the knobs & flip the switches to make my Strat sound like a Gibson ... one of my nieces or nephews is usually playing the '61 at the time ;-)

          Yes, I run a couple McIntosh-based sound systems.

          No, I'm not a deadhead, despite being from Palo Alto and the right age ... Never did think they had much to offer ... To me, all their music sounded the same ... 30 years of mediocrity ... but then I don't smoke pot. ::shrugs::

  12. JimmyPage

    I hear military ears pricking up ....

    I recall years ago (1981 ?) a massive front cover on Electronics Today International (ETI), warning of the perils the advanced tech of the West faced against the Electro Magnetic Pulse surrounding a nuclear blast - which would fry VLSI chips. They pointed out that maybe the Russians weren't so stupid with their valve radios - they were unafffected.

    Fast forward today, and I'm pretty sure a large part of the cost (and weight)of military-spec equipment is shielding to protect against EMP. The icon because it's obvious really ....

    1. Anonymous Coward
      Anonymous Coward

      I heard

      It may be just a rumour, but I heard that top space boffins have been using field-emission valve technology much like this for years, only with the complexity of FPGA's - like thousands and now millions of gates. These I understood had reached GHz speeds in the mid nineties.

      In space, vacuum is really easy to achieve, of course, but 150nm of air is about 1/3 of the mean free path (500nm) - so there will be a 30% reduction in gain, which sounds acceptable. .

      1. Graham Wilson

        Re: I heard - - Right, I think.

        "space boffins have been using field-emission valve technology much like this for years"

        As I mentioned earlier, I've heard this before too, moreover I've seen photos of these valves in a magazine. That was a long time ago, at least 20 or more years.

        Compared with traditional valves, they were very small indeed but certainly not on a nano scale.

    2. Graham Wilson

      @JimmyPage -- Re: I hear military ears pricking up ....

      Hum, now you mention it, I seem to recall that ETI too. EMP was a big deal back then.

      The other issue would be particles from large solar flares. If we had a solar storm the size of the 1859--biggest on record--then it's probably by-by to most of the satellites (the 1859 storm was powerful enough to disrupt ordinary terrestrial non-electronic Morse telegraph circuits (and that's as simple as it gets--wire, a battery, key and sounder).

      I'm still sceptical about whether these nano valves would be safe from EMP as they seem to use a Si/semiconductor substrate which would likely short in an EMP event (although this would probably be only temporary if the Si was amorphous and junction-less).

  13. Purlieu


    Valves are immune from EMP

  14. Anonymous Coward
    Anonymous Coward

    ...some of the earliest digital devices...??

    Since when were thermionic valves (vacuum tubes) digital devices?

    Sure, valves were used in digital equipment before being widely supplanted by transistors but even transistors are intrinsically analogue devices. Digital utilisation, with both types of device, just comes down to using discrete bands of analogue levels within the continuous range of levels the devices are capable of.

    1. Robert E A Harvey

      re:Since when were thermionic valves (vacuum tubes) digital devices?

      Since W,H. Eccles, F.W. Jordan, "Improvements in ionic relays" British patent number: GB 148582 (June 1918)?

      or O. E. Schmitt [Jour. Sci. Instr., 15, 24-26 (1938)] ?

      Both transistors & themionic valves are linear devices that at the extremety of the load lines exhibit switch-like voltsdrop & pass currrent values. By saturating them hard you can defone two discrete states with a rapid transition between them.

      Seems just as digital as a transistor to me.

      1. Anonymous Coward

        Re: re:Since when were thermionic valves (vacuum tubes) digital devices?

        It seems rather disingenuous to use a quote that starts by explicitly referring to linear devices as justification for claiming that they're switching devices when the switching behaviour only occurs if the devices are being operated outside their design parameters. It's about as valid as describing an automobile as an aircraft on the reasoning that when it's driven off a cliff it travels through the air.

        1. Graham Wilson

          @LeeE -- Re: re:Since when were thermionic valves etc... -- Your point is a non-sequitur!

          Your point is a non-sequitur--useless.

          For heaven's sake, Robert E A Harvey is correct as he's just stating the well-known fact that valves once had widespread use in digital electronics. Moreover, when valves were used in digital applications they operated fully within their designed operational parameters.

          Fact: Eccles and Jordan invented what's known as the Eccles-Jordan flip-flop aka multivibrator circuit, which is intrinsically a digital circuit AND IT ORIGINALLY USED VALVES/TUBES (practical semiconductor flip-flops had to wait until the perfection of the transistor some 20 years later in 1947). No argument!

          The Eccles-Jordan and similar digital circuits were used in hundreds of applications before the transistor was perfected in '47. Notable digital applications that used valves/tubes include the sync timebase for 405-line TV--the first all-electronic television system invented in the 1920s by the famous EMI/Alan Blumlein team; Colossus, the first true digital computer used during WWII for code-braking at Bletchley Park, and also digital circuits found application in many other WWII electronics such as RADAR etc. Furthermore, various flip-flops were used in just about every TV set that used valves (i.e.: all TV sets worldwide made from 1930s to the early 1970s).

          Fact: valves can act as switches by saturating or current limiting/running into clipping or hard-biasing them etc.--the circuits are numerous. When used in linear circuits such as audio and operational amplifies, valves are in fact harder to keep linear than transistors. For example, in an audio amplifier that uses valves it's hard to reduce the distortion to below about 1% although it can be done with effort, whereas it's not unusual to see a solid-state/transistor amplifier with a distortion in the order of 0.001% or less--and remember it's the transistor which is at the heart of modern-day digital electronics--not the valve. (It puts paid your stated argument that analog valves can't be used in digital electronics.)

          Interesting fact: a single valve can act as both a digital switch and as a linear amplifier simultaneously! And this circuit, the super-regenerative receiver, was invented just on 100 years ago in 1913--some five years before the Eccles-Jordan flip-flop--by Edwin Armstrong, (Armstrong also invented the normal radio circuit that's almost exclusively used today--the superheterodyne receiver, and remarkably, he also invented FM radio).

          The super-regenerative receiver is truly remarkable: [what follows is very simplified] a SINGLE VALVE, usually a simple triode, amplifies tiny RF signals received by the antenna using a regenerative positive-feedback process, it then quenches the feedback (stops the feedback taking off into a useless howl) with an oscillating/switching (digital) signal that's about double the frequency of the highest audio signal received, and so doing it detects the signal by rectifying it which is a diode-like switching process which makes the modulation on the RF carrier audible; and finally, it amplifies the detected audio signal which is then fed to the listener.

          All up, the super-regen RX can amplify a weak radio signal up to about one million times in a single valve and it does so by simultaneously making use of both analogue (linear) and digital (switching) techniques.

          This remarkable circuit was used in British aircraft during the Battle of Britain for the IFF (Identification Friend or Foe) equipment to stop allied aircraft mistakenly shooting each other down in the dark. What's more, IFF was bidirectional, it also had to transmit as well as receive signals--and incredibly it also did the transmitting whilst simultaneously using the very same valve for receiving. Beat that!

          In the whole history of electronics, no other circuit has done so much with so few components.

          1. jake Silver badge

            @Graham Wilson (Was: Re: @LeeE -- ::snippage:: -- Your point is a non-sequitur!)

            Unfortunately, Mr. Wilson, the kiddies born of TheNintendoGeneration[tm] don't want to listen to us boring old farts. That's why they are making the same mistakes we made over the last 40 decades in the business ...

          2. Anonymous Coward
            Anonymous Coward

            Re: @LeeE -- re:Since when were thermionic valves etc... -- Your point is a non-sequitur!

            You've used an awful lot of words to make the same point I did in my original post: "Sure, valves were used in digital equipment..."

            The output from valves and transistors is proportional to the input on the grid/base so the devices are intrinsically analogue; the output from a true digital device would not be proportional to its controlling input.

            Neither is linearity, or lack of it, a factor. More pertinent is Robert E A Harvey's point: "By saturating them hard you can defone (sic) two discrete states with a rapid transition between them".

            This is absolutely true, but the key points here are 'define two discrete states' and 'rapid transition'. Firstly, the two states have to be defined because they are not inherent whereas in a true digital device there would be no need to define the two discrete states because they would be inherent. Secondly, whilst the transition between the two states may be 'rapid' the transition between the two states in these devices requires that the level passes through intermediate values whilst it does so whereas a true digital device would not have intermediate levels and could only be at one level or the other; the rapidity of switching doesn't really come into it (although in a truly digital device you'd still need to wait for the superposition of the two states to resolve [to one state or the other] before you could use it).

  15. Anonymous Coward
    Anonymous Coward

    With a bit more effort they might be able to catch up to the work that was being done at Cambridge 15 years ago. Woohoo!

  16. nijam Silver badge

    I thought the earliest electronic devices were the so-called "cat's whisker" primitive semiconductors, and valve were a Johnny-come-lately?

  17. Mike 16

    Before cat's whiskers ...

    we had coherers. Typically called "Branly Coherers", due to Stigler's law ( Nothing is ever named for its actual discoverer). That's for the receiver. Transmitters were spark-gaps, internationally forbidden in the 1920s, but I have beside me as I type a toy using both these items, from the 1950s.

    Also from the 1950s (and more relevant) Sylvania's ceramic multi-component modules (think: macro-scale I.C.s). incorporating thermionic valves, and intended for space use.

    1. John Smith 19 Gold badge

      Re: Before cat's whiskers ...

      Also from the 1950s (and more relevant) Sylvania's ceramic multi-component modules (think: macro-scale I.C.s). incorporating thermionic valves, and intended for space use."


      Project Tinkertoy?

  18. Argus Tuft

    ahhh memories...

    6146B's happily warming the room- - back when there was still some magic in talking to someone on the other side of the world, and international phone calls upped your mortgage...

    then came computers... sigh....

    1. Graham Wilson

      @Argus Tuft - - Re: ahhh memories...

      Yuh Johnny-come-lately with new-fangled toys. The bracers brigade use 100THs for size.

  19. John Smith 19 Gold badge

    Anyone notice 460Ghz operating frequency?

    Not bad for a prototype.

    There are articles in the GEC Journal of research (the UK GEC) dating IIRC from the late 80s, early 90s on individual triodes and the articles mentioned at least one of the US national labs (Lawrence Livermore or Los Alamos most likely) due to the exceptional radiation hardness.

    The GEC stuff was IIRC evacuated rather than being ambient pressure and relying on the device scale being small enough that the mean free path would not matter.

    I suspect this will also have link into what are referred to as "Ballistic" transistors due to the path the electrons take within the silicon.

    As for the power levels people are complaining about doesn't that depend on how *many* electrons are needed to be moved to switch from 0 to 1? Single electron transistors *already* exist.

    On a general design note *all* digital logic is essentially *analog* circuitry driven hard enough to suppress (in principle) any sensitivity to low level analog problems while taking a hit on speed (ECL traded complexity for speed by going sub saturation and so being 10x faster than top end TTL but with huge power needs).

    Large scale and/or high frequency digital design problems arise when they can't be driven hard enough (usually there's so damm many transistors you can't pump enough power into the chip without melting it).

    460Ghz processor anyone?

    Yes. I think it will play Krysis.

    1. Graham Wilson
      Thumb Up

      @John Smith 19 - - Re: Anyone notice 460Ghz operating frequency?

      "On a general design note *all* digital logic is essentially *analog* circuitry driven hard enough to suppress (in principle) any sensitivity to low level analog problems while taking a hit on speed..."

      Correct, it's hard to get this point across to digital types who've had little small-signal analog experience. That's why I used the example of the super-regenerative receiver in my post above, it neatly illustrates (albeit in a complex way) how digital switching and analogue amplification are essentially a part of one large analog process.

      Of course, at the purely quantum level, it's back to 'digital' again for electrons. (And this brings up the usual nomenclature/definition problem: as the terms 'analog' and 'digital', having had a somewhat checkered past as far as common usage goes, we really should define them more precisely to avoid confusion).

      Re 460GHz, I mentioned that too somewhere above. Not bad really given that it's not that long ago valves had problems just working in the UHF region. Mind you, 460GHz [lambda ~ 0.5mm] still falls short if you ever wanted to use the technology for a 1000nm laser (~3000,000GHz).


      1. Anonymous Coward

        Re: @John Smith 19 - - Anyone notice 460Ghz operating frequency?

        Now you've got me confused. Earlier you seemed to be arguing with me that valves and transistors can be regarded as digital devices yet here you're saying the opposite and agreeing with my original point that whilst these devices can be used in digital applications they are still fundamentally analogue devices.

        1. John Smith 19 Gold badge

          Re: @John Smith 19 - - Anyone notice 460Ghz operating frequency?

          I'm not arguing with anyone. It's a matter of scale.

          Grossly overdriven analog stages with feedback -> Digital

          Lower the signal levels and the feed back -> small signal effects -> analogue operation (In a pinch smart designers have used individual inverters from a TTL chip as analog amplifiers. These are *highly* constrained designs where you simply cannot add a package).

          This is the milliamp/millivolt level down to micro amp/volt levels. Signal levels that would get lost in the hash of the power lines on a digital board (part of what makes putting sound and video signals on PC so "interesting").

          Lower it further . 1mA is still 6.25 x 10^12 electrons. In the 1950s people made op-amps with input currents at the *pico* amp level. That is still 6.25 million electrons. At the single electron transistor level there is *one* electron. It is either there or not, which is about as *indivisible* as you can get (image intensifiers are also quantum devices. That "flickering" you get in NV devices is *not* a mfg fault. It's the quantum nature of reality itself)

          If you *really* want to go digital you're looking at electron transitions in atoms. The levels are fixed, *highly* stable and (AFAIK. IANAQP) they cannot be sub-divided. You can't get an electron caught half way between two levels.

          Engineering a system to link atoms together and use those transitions to build a "true" digital system is left as an exercise.

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